Journal of experimental zoology V30

THE JOURNAL OF EXPERIMENTAL ZOOLOGY EDITED BY Jacques Loeb William E Castle The Harvard University Edwin Edmund G Conklin B Rockefeller Institute Wilson Columbia University Princeton University Charles B Thomas H Morgan Davenport Columbia University Carnegie Institution George H Parker Herbert S Jennings Harvaid University Johns Hopkins University Raymond Pearl Frank R Lillie Maine Agricultural Experiment Station University of Chicago Ross G Harrison, Yale Univcrsitj Managing Editor // VOLUME 30 JANUARY—MAY, 1920 THE WISTAR INSTITUTE OF ANATOMY AND BIOLOGY PHILADELPHIA, PA n CONTENTS No JANUARY The relations between nuclear number, chromatin mass, cytoplasmic mass, and shell characteristics in four sijccies of the genus Arcella Forty-seven figures Robert W Hegner C M Jackson and C upon the ultimate A Stewart The effects of inanition in the young size of the body and of the various organs in the Five charts 97 J A Dawson An experimental study of an amicronucleate Oxytricha II The formation of double-animals or 'twins.' Twenty-two figures 129 H Saxton Burr The transplantation of the cerebral hemispheres of albino rat Amblystoma Nine figures 159 No FEBRUARY H V Wilson and Blackwell Markham Asymmetrical regulation in anuran embryos with spina bifida defect Five figures 171 Bennet M Allen The results of earliest removal of the thymus glands in Rana pipiens tadpoles One figure Bennet M Allen The parathyroid glands 189 of thyroidless Bufo larvae 201 experimental study of cell-division I The physical conditions which determine the appearance of the spindle in seaurchin eggs 211 Caswell Grape Amaroucium pellucidum (Leidy) form constellatum (Verrill) I The activities and reactions of the tadpole larva Four L V Heilbrunn An 239 figures No Charles Howard Edmondson APRIL The reformation Mya arenaria after extraction Nine figures of the crystalline style in Thirty figures 259 Charles Zeleny A change in the bar gene of Drosophila melanogaster involving further decrease in facet number and increase in dominance Harold Cummins 293 The role of voice and coloration in spring migration and sex recognition in frogs 325 Henry Laurens and Henry D Hooker, physiological value of spectral lights to wave-lengths of equal energy content Jr II Studies on the relative The Two sensibility of Volvox 345 figures iii I (o^(o o CONTENTS IV Francis B Sumner Geographic variation and Mendelian inheritance 369 Seven figures C M Child Studies on the dynamics of morphogenesis and inheritance X Head-frequency in Planaria dorotoin experimental reproduction 403 cephala in relation to age, nutrition and motor activity No Edwin Carleton MacDowell MAY Bristle inheritance in Drosophila III 419 Eight figures Minna E Jewell The effects of hydrogen ion concentration and oxygen content of water upon regeneration and metabolism of tadpoles 401 Twenty-four figures Correlation THE JO-CRNAL OF EXPERIMENTAL ZOOLOGY, JANUARY, 1920 VOL 30, NO el autor, R W Hegner Universidad Johns Hopkins, Baltimore Resumen por el numero de nucleos, la masa de cromatina, masa citoplasmica y los caracteres de la concha de Las relaciones entre la cuatro especies del genero Arcella El presente trabajo contiene observaciones y experimentos sobre Arcella denta, A polypora, A vulgaris y A discoides Ejemplares de clones cuyo tamano y numero de espinas era cono- Los pedazos uninucleados de padres binucleados produjeron descendientes uninucleados que tenian aproximadamente la mitad del tamano de los padres Esto indica, por consiguiente, la relacion de una cantidad definida cido se cortaron en dos pedazos los de citoplasma un solo micleo Las masas decromatina fueron medidas en ejemplares procedentes de clones de A dentata que diferian en tamano y en numero de espinas; el autor comprobado que la cantidad de cromatina era menor en los ejemplares procedentes de los clones mas pequefios Es decir, que la cantidad de citoplasma varia directamente la cantidad de cromatina A polypora contiene de Ires a trece nucleos El numero de nucleos varia dentro de un clono, y el tamano enun mismo clono esta relacionado muy estrechamente el numero de nucleos Los ejemplares el mismo numero de nucleos, pero pertenecientes a clones diferentes pueden diferir en tamano Las medidas de las masas de cromatina demuestran que los ejem- mismo tamano pertenecientes a clones diferentes tienen aproximadamente la misma cantidad de cromatina, aunque el numero de nucleos sea diferente Esto indica que la cantidad de citoplasma no depende del numero de nucleos, sino de la can- plares del El autor discute los datos obtenidos referenda a la teoria de la relacion nucleocitoplasimca, la teoria de la relacion cromatocitoplasmica, las teorias de las lineas puras y de la seleccion, y la hipotesis de los cromidios tidad total de cromatina Translation by Jose F Nonidez Carnegie Institution of Washington author's abstract of this paper issued by the bibliogr.vphic service, octtobeh 13 THE RELATIONS BETWEEN NUCLEAR NUMBER, CHROMATIN MASS, CYTOPLASMIC MASS, AND SHELL CHARACTERISTICS IN FOUR PIECES OF THE GENUS ARCELLA^ ROBERT W HEGNER School of Hygie?ie and Public Health, The Johns Hopkins University FORTY-SEVEN FIGURES CONTENTS Introduction a The problem Advantages of Arcella for nucleocytoplasmic studies c Methods Experiments on Arcella dentata a Experiments on binucleate members of family 150 b Introduction Results of removing part of the shell and part of the cytoplasm The reproduction of uninucleate pieces Empty Correlations 12 Changes from binucleate to the uninucleate condition Reproduction of a uninucleate piece formed without an opera- 14 shell formation and nuclear doubling c d e 4 17 tion, line 159 Microdissection experiments Experiments on uninucleate specimens of family 150 Experiments on members of family 152 b 4 Experiments on members of family 58 of results of experiments on Arcella dentata Summary The observations and experiments described IS 21 27 28 31 in this paper were begun in the Hopkins University on December 27, 1917; were continued at the laboratory of the Brooklyn Institute of Arts and Sciences at Cold Spring Harbor, Long Island, from June 17 to August 27, 1918, and were completed at the School of Hygiene and Public Health of the Johns Hopkins University The writer is indebted to the members of the Zoological Department of the Johns Hopkins University for many courtesies and to Dr C B Davenport for the opportunitj' of carrying on work at Cold Spring Harbor He is particularly grateful to Prof H S Jennings for his valuable counsel Much of the statistical work was done by Dr Ruth Stocking Lynch, instructor in Protozoology in the School of Hygiene and Public Health ^ zoological laboratory of the Johns ROBERT W HEGNER Observations and experiments on Arcella polypora a Origin of the specimens studied h Relations between nuclear number and diameter in wild specimens c Variations in diameter within families d Relations between nuclear number and diameter within small families and between families e Relations between nuclear / 38 number 38 41 44 45 by cutting experiments Differences, between different families with regard to nuclear number and diameter Variations in nuclear number and diameter in wild specimens and within small families Differences between family ap and families ap 38, ap 39, ap and ap 34 Families ap 38, ap 39 and ap 69 h Family ap 34, Comparison of nuclear number and diameter with family ap Relation between diameter of shell and diameter of mouth in wild populations and within families Siunmary of results of observations and experiments on Arcella 69, /( 38 42 of nuclei nuclear number and their results Results of a further increase in nuclear number Uninucleate and binucleate specimens obtained in a g 36 off- spring Results of selection for lines with large and small diameters Relations between nuclear number and diameter during the selection period Results of selection for large and small diameters within groups Changes 35 a large fam- Family ap Correlation in diameter between parents and immediate 'with the same 35 37 number and diameter within ily 35 polypora Observations and experiments on Arcella discoides a Pure line h Variations in diameter and in nuclear number c The reproduction of uninucleate pieces d Summary of results of observations and experiments on Arcella discoides Observations and experiments on Arcella vulgaris The relations between chromatin mass and cell size a Chromatin mass and cell size within two families of Arcella dentata h Chromatin mass and cell size within two families of Arcella poljrpora c The possible relation between the chromatin mass and the death of certain specimens of Arcella dentata d Summary of the studies of chromatin mass and cell size Discussion 46 50 50 51 51 52 54 59 61 61 62 64 65 65 67 67 71 74 76 76 NUCLEOPLASMIC RELATIONS IN ARCELLA INTRODUCTION a The problem The investigations described in the following pages were undertaken to determine the relations between nuclear number, chromatin mass, cytoplasmic mass, and shell characteristics in certain species of the genus Arcella As a rule, genetic research in animals is limited to the study of somatic characteristics alone or to the examination of germ cells that have been killed and prepared for microscopic observation In many cases the germ cells of organisms that have been used in breeding experiments have been studied, but these germ cells have been obtained either from control specimens or from pedigree specimens that have been killed for the purpose Arcella is peculiarly favorable for investigation because both nuclear and cytoplasmic characteristics can easily be seen drawn and measured, at the same time, in the living animal, and their relations can thus be established under the most favorable circumstances h Advantages of Arcella for nucleocytoplasmic studies In a previous paper (Hegner, '19), various characteristics that Arcella a favorable organism for genetic investigations were pointed out Among these are: 1) the power of multiplying vegetatively and rapidly; 2) the presence of definite measurable characters that are not modified by growth; 3) the semitransparency of the shell which makes possible the examination of the make contents, especially in the recently formed offspring; 4) the ability to withstand severe operations, and, 5) the ease of cultiva- To be added the fact type with the chromatin, when in the resting stages, clumped into a spherical mass which may easily be drawn and measured It is thus possible to study the relation between chromatin and cytoplasm, which offers a much more accurate means of comparison than when the entire nucleus with the nuclear sap is involved tion and examination that the nucleus is this list should of the vesicular ROBERT W HEGNER c Methods The methods of rearmg the spechnens recorded m this paper same as those previously described (Hegner, '19) The operations were for the most part simple The specimens were first drawn with a camera lucida; they were then cut in pieces are the with a small, sharp scalpel, and the positions of the cuts were In one set of experiments the nucleus only was dissected out with the aid of a Barber microdissection apparatus Parts of specimens or those from which nuclei had been removed were cultivated as were the entire animals indicated on the sketch a EXPERIMENTS ON ARCELLA DENTATA Experiments on hinucleate members of family 150 Introduction The progenitor of this family (fig 1) was taken from a pond on the campus of the Johns Hopkins UniIts versity at Homew^ood, Baltimore, on December 27, 1917 spines consisted of almost indistinguishable ridges and could not be counted In diameter it measured 34 units of 4.3/i each Four immediate offspring were obtained from this specimen, all of which exhibited well-defined spines, showing that the absence of spines in the parent was probably due to some en^^ronmental factor The fourth offspring was represented by an empty shell; the other three possessed 13, 14, and 14 spines, was 34 units and the other two were 35 units respectively; one in diameter The (fig 2) Results of removing part of the shell and part of the cytoplasm first experiment was designed to answer the following ques- removed, is a new part regenerated? and its descendants has the removal of part of the cytoplasm and part of the chromidia? The Part of first offspring was operated on as indicated in figure the shell and some of the cytoplasm were removed No regeneration of the shell occurred The first offspring produced by this specimen after the operation was smaller than the parent (15-31 in fig 2), this decrease in size being due probably to the tions What If part of the shell is influence on a specimen ENVIRONMENT AND REGENERATION 497 tadpoles and the abnormal behavior of others during the experiment, no attempt was made to correlate the increase of CO2 production in bases or the decrease in acids with either weight The data show, on the whole, that the per cent increase or area of CO2 production in bases and the per cent decrease in acids both increase as the size of the tadpoles decreases Child ('18) shows that in Gonionemus the effects of abnormal hydrogen ion concentrations upon metabolism decrease as age In the majority of the author's experiments, however, increases there was no indication that the tadpoles differed in age or nearness to metamorphosis, and the few tadpoles which did show rudimentary hind legs did not differ appreciably nor always in the same direction from the physiologically younger tadpoles of the same size Experience in rearing tadpoles shows great variation in size in animals of the same age In view of these facts, it would seem that until parallel experiments can be performed upon animals of the same size, but differing in age, and of the same age, but differing in size, it must be regarded as an open question whether the relatively greater effect of abnormal hydrogen ion concentrations upon CO2 production in smaller tadpoles may not be due simply to the relatively larger area exposed to the unfavorable medium The surviving tadpoles of the preceding experiment were operated upon and allowed to undergo regeneration in the same solutions as the CO2 determinations had been made for The concentrations used had no effect upon regeneration in the largest size The medium-sized tadpoles w^ere affected only in the case of H2SO4 in which regeneration was noticeably retarded, while in the few of the smaller tadpoles which survived to regenerate the regeneration was markedly depressed A on the effect of size on regeneration was run in and 60 cc 0.01 N HCl made up to liter in 10-inch final series 30, 40, 50, crystallizing dishes, sizes Two each containing ten tadpoles of three distinct controls were run All of the tadpoles in the highest concentration died without regeneration Throughout the ex- periment the smaller tadpoles showed a higher per cent of regeneration than the larger ones until a concentration was reached in MINNA 498 E JEWELL which most of them died In such a concentration the few which survived underwent very httle regeneration In a concentration in which most of the tadpoles Hved, however, if the per cent regenerated by each tadpole be divided by the per cent regenerated by its respective control, the result is approximately the same for all sizes This would indicate that the effect of an acid upon regeneration is relatively independent of the size of the tadpole that the effect is probably largely local upon the regener; is reached which seriously which regeneration is retarded ating tissue until a concentration affects the tadpole as a whole, after by the acid both directly and indirectly because of the impaired health of the parent animal, upon which the is dependent for nutriment individuals before it is This point is new growing tissue reached in the smaller in the larger ones These experiments, while few in number, would suggest the use of abnormal conditions, such as those produced by chemicals, as a promising method of attack for investigations upon the relation between new tissues and the organism as a whole Regeneration in low oxygen The method oxygen has already For the first series of experiments three tadpoles of different sizes were placed in each of the seven experimental jars During this experiment the water was strongly basic to phenolphthalein, though acid to thymolphthalein Of the larger tadpoles, 70 to 77 mm., the one in the first jar (ox^^genfree water) died without regeneration, and no in 1.6 cc O2 per liter^ showed better regeneration than nos and in 3.03 and 3.8 cc O2 per liter, respectively This is doubtless accounted for by the fact that nos and remained most of the time at the surface of the water, while nos 4, 5, 6, and remained at the bottom, coming to the top only occasionally When the fact that the water in which nos and actually remained contained considerably more oxygen than was shown by the titrations is taken into consideration, these data show clearly a relation between regeneration and the oxygen content of the water The same thing is true of the medium-sized tadpoles been described — of obtaining a gradient of (p 466) — — ENVIRONMENT AND REGENERATION 499 Of these nos and remained at the top and underwent regenerNo 2, which did not show this response, died without regeneration Nos 4, 6, and 7, which remained at the bottom, underwent progressively better regeneration The results for the small tadpoles, 34 to 37 mm., are quite typical of what occurred each time an attempt was made to use small tadpoles in oxygen experiments Nos 1, 2, and remained at the top of the water Nos and lived twelve days and underwent slight regeneration Nos 4, 5, 6, and stayed at the bottom, and of these only no survived to undergo any regeneration, but its regeneration was ation apparently normal Here again, as was shown for the acids and bases, we find the susceptibility of the tadpole as a whole as compared to the susceptibility of the regenerating part higher in smaller than in larger tadpoles were carried on in water kept and from acid to slightly basic to phenolThe temperature was also corrected by the introducphthalein tion of the air coil which warmed the water to room temperature All subsequent experiments basic to rosalic acid, All of the tadpoles it entered the experimental jars chosen were large and showed rudimentary hind legs, as it was found that tadpoles at this stage remain at the bottom of the jars better than those in earlier stages The oldest tadpoles used had a total length of 75 to 85 mm., and the hind legs were two-jointed and digited, and stood out from the body so as to be visible from the dorsal aspect The results of this series before 21) again show a close correspondence between the oxygen and the rate of regeneration Figure 23 is a curve drawn from these same data representing the length of time necessary to regenerate 20 per cent of the (table 7, amount fig of in increasing concentrations of oxygen A comparison of this curve with the curves of Krogh ('14 a, b) for increase in the rate of development at increased temperatures and the toxicity curves of Powers ('18 b) for the decrease in length of life with increase in concentration of toxic substances shows that they are only in part similar If the author's curves amount removed for retardation of regeneration in bases and acids and for increased MINNA 500 E JEWELL carbon-dioxide production and oxygen consumption in bases, and Powers' curve for oxygen consumption in increasing amounts of anaesthetics had been drawn with the maximum concentration used (that is, a concentration just sufficient to prevent regener- ation or to cause the death of the organism) taken as the zero of the ordinate instead of with the control, or absence of the harmful factor, as zero all of the curves mentioned would be somewhat similar In all the theoretical zero falls far below the actual zero The final accident experiment of the oxygen series owes its value to an of this series were 71 to 76 mm long and The tadpoles TABLE Regeneration in low oxygen CC O2 PER LITER ENVIRONMENT AND REGENERATION c.c.a 4.0 501 MINNA 502 E JEWELL on the twenty-sixth day of the experiment showed that the first jar, which had regenerated only 2.8 per cent during the twenty-two days preceding the aeration of the water, had regenerated 19.8 per cent in the four days following it The tadpoles previously in higher amounts of oxygen, of course, showed less difference This experiment is of value as demonstrating that the increase in the higher amounts of oxygen is due to the oxygen, and not to any slight rise in temperature in the successive jars, or to a decrease in the alkalinity of the water as it takes up carbon dioxide produced by the successive tadpoles tadpoles in the Regeneration in low temperatures It has long been known that low temperatures, if not so low as to produce detrimental effects, may retard or completely check the development of certain animals for a considerable period of time, the animal still retaining power to complete normal development The following experiment was planned to test whether this might be true for regeneration Three sets of four tadpoles each were selected The first set was kept at room temperature 19° to 21°C.; the second was kept in a water-bath — and the third was kept in a refrigeration tank at 0° to 4° The first set underwent regeneration rapidly, the rate of the second set was considerably retarded, the third set underwent no regeneration whatever (table 8, fig 24) WTien the first set had completed regeneration, two from the third set were transThe day in which they were transferred to room temperature ferred and several succeeding days were cool, so the temperature For this reason, probably, the of the water stood at 18° to 19° regeneration of these tadpoles was slightly slower than that of the controls, although the growth curves are similar The two at 14°, tadpoles left at the lower temperature died without regeneration at the end of forty-seven days ENVIRONMENT AND REGENERATION 503 GENERAL DISCUSSION In comparing the effects upon metabolism of abnormal hydrogen ion concentrations, low Oxygen, and low temperature, it is of interest to note that alike they cause decrease in both the rate of regeneration and the total amount regenerated Were the effects of these agents due wholly to their action in retarding the metabolism and consequent division and growth of the the total cells would not be a decrease in amount ultimately regenerated, but rather an increase of the regenerating parts, the result TABLE Effect of temperature on regeneration MINNA 504 JEWELL E It was further noticed throughout these experiments that the appearance of pigment in the regenerated part, which may be supposed to show a certain stage of differentiation, occurred as early or earher in the tadpoles in high concentrations of acids or bases as in the controls; at about the same time in the low oxygen water, and somewhat later in the low temperatures From this it would seem that growth and differentiation (if appearance of pigment be accepted as a criterion of differentiation) in the regenerating parts are differently affected by the environ- mental agents studied, so that a hydrogen ion concentration, an oxygen content of the water, or a temperature of the surrounding medium which retards one process may have Uttle or no effect upon the other If, then, as is frequently supposed, the presence of differentiated tissue be the inhibitory factor which causes the cessation of growth of the new part, this difference in effect upon growth and differentiation by the environmental factors considered would account for the differences in the ultimate amount regenerated in the various concentrations of hydrogen ions and oxygen or at the various temperatures SUMMARY A study has been made of the effects of various conditions of hydrogen ion concentration, deficiency of oxygen and low temperature upon regeneration and oxygen metabolism in tadpoles of Rana clamata These studies show that the optimum hydrogen ion con- centration for regeneration probably between pH 6.7 is and concentration varies from the neutrality, pH 7.6 optimum or near neutrality, As the hydrogen ion in the direction of either acidity or basicity, both the rate of regeneration amount regenerated decrease, at first and the total gradually and then very and 17) upon regeneration of any given hydrogen ion concentration is practically the same for all stages of regeneration (p 488; figs 8, 11, 12, 14, 16, and 18) rapidly (figs 1, 2, 5, 6, 9, 10, 13, 15, The relative effect ENVIRONMENT AND REGENERATION Unfavorable hydrogen ion concentrations inhibit regener- ation directly by 505 by and indirectly affecting the regenerating tissue, The affecting the tadpole as a whole independent of the direct effect is relatively size of the tadpole, the indirect effect is greater in smaller tadpoles (p 498) In water of low oxygen content both the rate of regeneration and the total amount regenerated are dependent upon the amount of oxygen present (table 7; figs 21, 22, and 23) Both the rate of regeneration and the total amount regener- ated decrease with a decrease in temperature (table 8; fig 24) The phenomena of differentiation in regenerating tissues, by the appearance of pigmentation, are not retarded same extent by unfavorable hydrogen ion concentrations, insufficient oxygen, or low temperatures as are the phenomena as indicated to the of growth or elongation decrease in the total This, it is suggested, may explain the amount ultimately regenerated due to the unfavorable environmental factors studied (p 504) Carbon-dioxide production is increased by bases and decreased by acids A high rate of carbon-dioxide production, when induced by a basic medium, rate of regeneration (table 3; Both the acids and the is not correlated with a high figs 7, 8, 9, and 10, 11, 12) relative decrease of carbon-dioxide production in relative increase of carbon-dioxide production in bases increase as the size of the tadpole decreases (p 497) Although the extent to which any environmental factor may affect a given life process may vary with size, age, etc (p 497), and although different processes in the same individual may be affected to a different extent by the same environmental factor (p 504), it is suggested that unsuitable hydrogen ion concentrations, insufficient oxygen, low temperatures, and toxic substances affect development, regeneration, oxygen metabolism, and duration of life in the same way and according to the same laws This work was done in the Zoological Laboratory of the University of Illinois, under the direction of Dr V E Shelford, to whom the writer is indebted for many courtesies and valuable MINNA 506 The suggestions writer is E JEWELL also indebted to Dr Charles Zeleny methods used in the work on regeneraand to Dr E B Powers for many useful suggestions regard- for advice concerning the tion, ing details of the work LITERATURE CITED On the toxicity of distilled water for fresh-water grammarus BuLLOT, G Suppression of this toxicity by the addition of small quantities of sodium chloride U of Cal Pub., Physiology, vol 1, pp 139-141 Child, C M 1913 Studies on the dynamics of morphogenesis and inheritance 1904 experimental reproduction V The relation between resistance to depressing agents and rate of metabolism in Planaria dorotocephala and its value as a method of investigation Arch Entw Mech Org., in Bd 14, S 153-206 Physiological senescence in Hydromedusae 1918 Biol Bui'., vol 34, pp 49-63 / Dreyer, George M., and Walker, E W 1914 The determination of the minimal lethal dose of various toxic substances and its relationship to the body weight in warm-blooded animals, together with considerations bearing on the dosage of drugs Proc Roy Soc London, vol 87 B, pp 319-330 Haas, A R 1916 The effect of the addition of alkali to sea-water upon the hydrogen ion concentration Jour B ol Chem., vol 26, pp 515-517 Krogh, August 1914 a On the influence of temperature on the rate of em- bryonic development Zeit all physiol., Bd 16, S 163-167 1914 b On the relation of development and carbon-dioxide production Zeit all of chrysalides of tenebrio molitor at different temperatures Physiol., Bd 16, S 178-190 Levy, R L., Rountree, L G., and Marriott, W McKim 1915 A simple method for determining variations in the hydrogen ion concentration Arch Int Med., vol 16, pp 389-405 von Alkalien und Sauren auf die embryonale Entwickelung und das Wachstum Arch Entw Mech Org., Bd 7, of the blood LoEB, J tlber den Einfiuss 1898 S 631-641 On the relative toxicity of distilled water, sugar solutions and solutions of the various constituents of sea-water for marine animals 1903 U of Cal Pub., Physiology, vol 1, pp 5.5-69 the influence of the reaction of the sea-water on the regeneration and growth of tubularians U of Cal Pub., Physiology, On 1904 vol LoEB, J., 1, pp 139-141 AND Wasteneys, H 1913 a The relative influence of weak and strong bases upon the rate of oxidation in the unfertilized eggs of the seaurchin 1913 b eggs Jour Biol Chem., vol 14, pp 355-361 influence of bases upon the rate of oxidation in fertilized The Jour Biol Chem., vol 14, pp 459-464 ENVIRONMENT AND REGENERATION 507 McClendon, 1916 Hydrogen and hydroxyl ion concentration in physiJ F ology and medicine Medical Review of Reviews, vol 22, pp 333-365 Medes, Grace 1918 A study of the cause and extent of variation in the larvae of arbacia punctulata Jour Morph., vol 30, pp 317-432 Moore, Benjamin, Roaf, H lies E., and acids and and Whitley, E division in the fertilized London, OsTERHOUT, J V 1905 On the effects of alka- and acid salts upon growth and cell eggs of Echinus esculentus Proc Roy Soc of alkaline vol 77B, pp 102-136 Effect of acids on permeability 1914 Jour Biol Chem., vol 19, pp 493-501 Powers, E B 1918 a A collection bottle especially adapted for the quanti- tative and qualitative determination of dissolved gases, parti cularly very small quantities of oxygen Bull 111 State Lab Nat Hist., vol 11, pp 577, 578 1918 b The gold fish (Carassius carassius L.) as a test animal in the study of toxicity 111 Biol Mon., vol 4, no Shelford, V E 1918 Equipment for maintaining a flow of oxygen-free water and for controlling gas content Bull 111 State Lab Nat Hist., vol 11, pp 573-575 E., and Powers, E B 1915 An experimental study of the movements of herring and other marine fishes Biol Bull., vol 28, Shelford, V pp 315-334 1915 Reaction and resistance of fishes in their natural environ- Wells, M M ment to acidity, alkalinity and neutrality Biol Bull., vol 29, pp 221-257 Whitley, E 1905 A note on the effect of acid, alkali and certain indicators in arresting or otherwise influencing the development of the eggs of platessa and Echinus esculentus Proc Roy Soc Pleuronectes London, vol 77B, pp 137-149 Wright, A H 1914 North American Anura, Washington Zeleny, Charles 1916 Studies on the factors controlling the rate generation 111 Biol Mon., vol 3, no of re- SUBJECT AND AUTHOR INDEX ACTIVITIES and reactions of the Chromatin mass, cytoplasmic mass, and tadpole larva Amaroucium pellucidum (Leidy) formconstellatum (Verrill) I The Studies on the dynamics of morphogenesis and inheritance in experimenX Head-frequency in tal reproduction Planaria dorotoccphala in relation to age, nutrition and motor Age, nutrition and motor af-tivity Studies on the dynamics of morphogenesis and inheritance in experimental reproduction X Head-frequency in Planaria dorotocephala in relation to Albino rat The effects of inanition in the young upon the ultimate size of the body and of the various organs in the Allen, Bennet M The parathyroid glands 239 of thyroidless Bufo larvae Allen, Bennet M The results of earliest removal o! the thymus glands in Rana pip- shell characteristics in four species of the genus Arcella The relations between nuclear number Activity Coloration in spring migration and sex recognition in frogs Constellatum 403 403 97 201 iens tadpoles 189 (Leidy) form constellatum (Verrill) I The activities and reactions of the tadpole larva 239 Amblystoma The transplantation of the The (Verrill) role of voice and 325 I The activities and reactions of the tadpole larva Amarouciurn pellucidum (Leidy) form 239 Correlation Birstle inheritance in Drosophia Correlation Bristle inheritance in Drosophila Ill 419 Crystalline style in Mya arenaria after extraction The reformation of the 259 Cummins, Harold The role of voice and coloration in spring migration and sex recognition in frogs 325 Cytoplasmic mass, and shell characteristics in four species of the genus Arcella The relations between nuclear number, chromatin mass Amaroucium pellucidum cerebral hemispheres of 159 AmicTonucIeate Oxytricha II The formation of double-animals or 'twins An experimental study of an 129 Anuran embryos with spina bifida defect ' Asymmetrical regulation in 171 Arcella The relations between nuclear number, chromatin mass, ctyoplasmic mass, and shell characteristics in four species of the genus Arenaria after extraction The reformation of the crystalline style in Mya 259 Asymmetrical regulation in anuran embryos with spina bifida defect " 171 gene of Drosophila melanogaster inBARvolving further decrease in facet number and increase in dominance A change in the of J A An experimental study Oxytricha II double-animals or an amicronucleate The formation of twins' Defect Asymmetrical regulation in anuran embryos with spina bifida Dominance A change in the bar gene of Drosophila melanogaster involving further decrease in facet number and increase in Dorotocephala in relation to age, nutrition and motor activity Studies on the dynamics of morphogenesis and inheritance in experimental reproduction X Head-frequency in Planaria Double-animals or 'twins.' An experimental study of an amicronucleate Oxytricha ' II The formation 129 171 293 403 129 of Drosophila III Correlation Bristle inheritance in 419 Drosophila melanogaster involving further decrease in facet number and increase in dominance A change in the bar gene of 293 Dynamics of morphogenesis and inheritance in experimental reproduction X Headfrequency in Planaria and dorotocephala 293 Asymmetrical regulation in anuran embryos with spina Bifida DAWSON, defect 171 Bristle inheritance in Drosophila III Correlation 419 Bufo larvae The parathyroid glands of thyroidless 201 Burr, H Saxton The transplantation of the cerebral hemispheres of Amblystoma 159 in relation to age, nutrition, tivity and motor ac- Studies on the EDMONDSON, Charles 403 Howard The reformation of the crystalline style in Mya arenaria after extraction 259 An experimental study of cell-division The physical conditions which determine the appearance of the spindle in seaurchin 211 Embryos with spina bifida defect Asymmetrical regulation in anuran 171 Eggs I CELL-DIVISION I The physical conditions which determine the appearance of the spindle in sea-urchin eggs Anex- perimental study of Cerebral hemispheres of Amblystoma transplantation of the 211 The 159 Child, C M Studies on the dynamics of morphogenesis and inheritance in experimental reproduction X Head-frequency in Planaria dorotocephala in relation to age, nutrition, and motor activity 403 number and increase in dominance FACET A change in the bar gene of Drosophila melanogaster involving further decrease in 293 Frogs The rdle of voice and coloration in spring migration and sex recognition in 325 509 INDEX 510 GENE ing MAcDOWELL, of Drosophila melanogaster involvfurther decrease in facet number in dominance change Edwin Carleton inheritance in Drosophila A and increase Bristle III Cor- relation 419 in the bar 293 Geographical variation and Mendelian inheritance 369 Markham, Blackwell, Wilson, H Glands in Rana pipiens tadpoles The results of earliest removal of the thymus Glands of thyroidless Bufo larvae The para- 201 Melanogaster involving further decrease in facet number and increase in dominance A change in the bar gene of Drosophila 293 Mendelia,n inheritance Geographic variation (Leidy) form constellatum (Verrill) I The activities and reactions of the tadpole 239 larva Metabolism of tadpoles The effects of hydrogen ion concentration and oxygen content of water upon regeneration and 461 thyroid 189 Grave, Caswell Amaroucium pellucidum V., and Planaria dorotocephala in relation toage, nutrition, and motor activity Studieson the dynamics of morphogenesis and inheritance in experimental reproduction 403 X relations between nuclear number, chromatin mass, cytoplasmic mass, and shell characteristics in four species of the genus Arcella L V An experimental study of cell-division I The physical conditions which determine the appearance of the spindle in sea-urchin eggs 211 Hemispheres of Amblystoma The transplantation of the cerebral 159 Hooker, Henry D., Jr., Laurens, Henry, AND Studies on the relative physiologica' value of spectral lights II Thesensi- Heilbrunn, bility of Volvox to wave-lengths of equal energy content 345 ion concentration and oxygen content of water upon regeneration and metabolism of tadpoles The effects of 461 Hydrogen INHERITANCE Geographic variation and Mendelian 369 Inheritance in Drosophila III Correlation 419 Bristle in experimental reproduction X Head-frequency in Planaria dorotocephala in relation to age, nutrition, and motor activity Studies on the dynamics Inheritance morphogenes is and Inanition in the young upon the ultimate of poles The effects of hydrogen 97 Planaria dorotocephala in relation to age, Mya arenaria after extraction The reformation of the crystalline style in 259 NUCLEAR number, chromatic mass, cyto- plasmic mass, and shell characteristics in four species of the genus Arcella The relations between Number and increase in dominance change in the bar gene of Drosophila melanogaster involving further decrease in facet 293 Nutrition and motor activity Studies on the dynamics of morphogenesis and inheritance in experimental reproduction X Head-frequency in Planaria dorotocephala in relation to age 403 A content of water upon regenerOXYGEN ation and metabolism of tadpoles The hvdrogen ion concentration 461 The formation of doubleanimals or 'twins.' An experimental 129 study of an amicronucleate II PARATHYROID Bufo larvae 461 various organs in the albino rat 97 Jewell, Minna E The effects of hydrogen ion concentration and oxygen content of water upon regeneration and metabolism 461 of tadpoles Amaroucium pellucidum (Leidy) I The acof the tadpole 239 parathyroid glands of thyroid201 (Verrill) and reactions Larvae The less Bufo Laurens, Henry, and Hooker, Henry D., Studies on the relative physiological value of spectral lights II The sensibility of Volvox to wave-lengths of equal energy content 345 Jr The sensibility of Volvox to wave-lengths of equal energy content Studies on the relative physiological value 345 of spectral Lights II thyroidless 201 The activities and reactions of 239 the tadpole larva Amaroucium Pipiens tadpoles The results of earliest re189 moval of the thymus glands in Rana Planaria dorotocephala in relation to age, nutrition, and motor activity Studies on the dynamics of morphogenesis and inheritance in experimental reproduction rill) I X Head-frequency in RANA pipiens tadpoles removal of the earliest tivities glands of The Pellucidum (Leidy) form constellatum (Ver- C M., AND Stewart, C A The effects of inanition in the young upon the ultimate size of the body and of the form constellatum 325 nutrition, and motor activity Studies on the dynamics of 403 Motor activity Studies on the dynamics of morphogenesis and inheritance in experimental reproduction X Head-frequency in Planaria dorotocephala in relation to age, nutrition and 403 effects of JACKSON, LARVA The in spring and size of the body and of the various organs in the albino rat The effects pf Ion concentration and oxygen content of water upon regeneration and metabolism of tad- and coloration role of voice I Morphogenesis and inheritance in experimental reproduction X Head-frequency in Oxytricha 403 171 36 Migration and sex recognition in frogs HEAD-FREQUENCY in Hegner, Robert W The and Asymmetrical regulation in anuian embryos with spina bifida defect Rat The 403 The results of thymus glands 189 effects of inanition in the size of the body upon the ultimate young and of the various organs in the albino Reactions of the tadpole larva Amaroucium pellucidum (Leidy) form constellatum 97 239 (Verrill) I The activities and The r61e of voice and 325 coloration in spring migration and sex of the crystalMne style in Mya 259 arenaria after extraction The Regeneration and metabolism of tadpoles The effects of hydrogen ion concentration 461 and oxygen content of water upon Recognition in frogs Reformation INDEX TADPOLE Regulation in anuran embryos witi bifida defect Asymmetrical la pipof the thymus glands in R iens tadpoles The results of ear lif st Removal Reproduction X Head-frequency naria dorotocephala in relation to a ria;e, nu- and motor activity Stu' ies on the dynamics of morphogenesis a nd inheritance in experimental study of eggs An cell-division I experifnental The conditions which determine the ance of the spindle in Sex recognition in frogs The role o voice and coloration in spring migration md Shell characteristics in four species of the genus Arcella The relations betclear number, chromatin mass, y toplasmic mass, and en nu- ( olvox Spectral lights II The sensibility of itent to wave-lengths of equal energy c|)ntent value Studies on the relative physiologic: of Asymmetrical embryos with Spina bifida defect tion in anuran Spindle in sea-urchin eggs An egula- experifnen tal study of cell-division I The p ppearconditions which determine the ance of the frogs Spring migration and sex recognition lyEsical i ; • • The role of voice and coloration i The Stewar?', C a., Jackson, C M., ani effects of inanition in the young u I on the ultimate size of the body and of he rious organs in the albino rat The Style in Mya arenaria after extractioi reformation of the crystalline Sumner, Francis B Geographic vajriation and Mendelian inheritance n larva dum (Leidy) rill) I The Amaroucium pelluci- form constellatum activities and (Verreactions of the Tadpoles The effects of hydrogen ion concentration and oxygen content of water upon regeneration and metabolism of Tadpoles The results of earliest removal of the thymus glands in Rana pipiens Thymus glands in Rana pipiens tadpoles The results of earliest removal of the Thyroidless Bufo larvae The parathyroid glands of Transplantation of the cerebral hemispheres trition, SEA-URCHIN 511 of ; Amblystoma The 239 461 189 189 201 159 'Twins.' An experimental study of an amicronucleate Oxytricha II The formation of double-animals or 129 VARIATION and Mendelian inheritance Geographic 369 Voice and coloration in spring migration and sex recognition in frogs The role of 325 Volvox to wave-lengths of equal energy content Studies on the relative physiological value of spectral lights II The sensibility of 345 WAVE-LENGTHS of equal energy con- tent Studies on the relative physiological value of spectral lights II The sensibility of Volvox to 345 Wilson, H V., and Markham, Blackwell Asymmetrical regulation in anuran embryos with spina bifida defect 171 ZELENY, Charles A change in the bar gene of Drosophila melanogastcr involving further decrease in facet increase in dominance number and 293 ... shape of the off6) spring are clearly indicated in figures and The immediate Pedigree of fiimily 150 showing the number of spines Fig Arcella dentata and diameter of the shell of the progenitor of. .. diameters and spine numbers of the uninucleate parents, of the empty shells they produced, of the first offspring formed after throwing the empty shells, and of the first offspring of the three succeeding... Outline of the shell of the progenitor of family 150 inner circle represents the mouth opening X 207 Fig Arcella dentata Outline of the shell of specimen 150.1 The cross line indicates the portion of