Monography of the family Unionidae (Fresh water Bivalve shells) of North America, Conrad 1833

.Vo M GR A N P HY FA3IILY UXIOXID.i! OR NAIADES OF LAMARCK ^FRESH WATER BIVALVE SHELLS.' OF NORTH AMERICA., ILLUSTRATED BV FIGURES DRAWN ON STONE FROM NATURE BY T A CO.\ HAD CURATOR OF THE ACADEMY OF NATURAL SCIENCES OF PHILADELPHIA THE GEOLOGICAL SOCIETY OF PENNSYLVANIA BOMBAST SMITHSONIAN INSTITUTION WASHINGTON 25, D.C# PHILADELPHIA: J DOBSON, E G LOG CHESNUT STREET DORSEY, PRINTER />• a ::' 1835 SIE1IBEK OF MONOGRAPHY OF THE FAMILY UNIONIDiE, OR NAIADES OF LAMARCK, (FRESH WATER BIVALVE SHELLS,) OF )H Of NORTH AMERICA, Sectional Library ILLUSTRATED BY FIGURES DRAWN ON STONE FROM NATURE BY T A CONRAD, CURATOR OP THE ACADEMY OF NATURAL SCIENCES OF PHILADELPHIA, HONORARY MEMBER OF THE GEOLOGICAL SOCIETY OF PENNSYLVANIA PHILADELPHIA: J DOBSON, 108 CIIESNUT STREET 1836 E G Dorsey, Printer, 12 Library Street TO CHARLES A POULSON, Member of the Academy of Natural THIS BOOK IS Esa Sciences of Philadelphia, tf-c DEDICATED, AS A SLIGHT TRIBUTE OF ESTEEM, BY HIS OBLIGED FRIEND, THE A UTHOR Y MONOGRAPH OF THE FAMILY UNIONIDil UNIO GENERIC CHARACTER Shell equivalved, inequilateral: cardinal teeth in each valve, irregular, generally two striated, simple or an elongated lamelliform tooth on the poshinge margin of the right valve, and two biparted; terior on the corresponding margin of the left valve: muscular impressions two principal ones in each valve similar teeth OBSERVATIONS Mr Say justly remarks, that, "in North America, any other the shells of this genus excel those of country in magnitude, beauty, and diversity of species." most The rivers of Tennessee have furnished the many species common to The Ohio or Mississippi has beautiful specimens of the western waters not hitherto furnished a single species existing in tide waters which flow into the Atlantic; only shell of this character gi?iata, The is and the the Alasmodonta mar- Say shells of this genus may be divided into two groups, the "winged" and "not winged," as Mr Sow- erby has proposed for the whole family of Unionid^e The former are included in the genus SympJiynota, of Mr Lea, which we cannot adopt, because, as Ferussac justly remarks, "in the same family generic characters should be taken from the same parts;" thus the other genera are formed from the absence or arrangement of the hinge teeth, whilst SympJiynota, without any regard to the hinge, is constructed from a testaceous connexion of the valves, which Ferussac observes is "almost an organic character among the Acephala which have the mantle completely closed near the hinge margin, at least in young shells." Dr Kirtland has made some interesting remarks the sexes of this family, in which he has proved on them many conchoand the sex can be ascertained by the form of the shell Almost every species has two prominent varieties of form, one of which is shorter and more ventricose than the other, which is happily exto be distinct, in the opinion of logists; plained by the observations of the intelligent author of the essay referred to.* *Vide Silliman's Journ vol xxvi p 117 Unto fascuttus.Raf 116 was a small valve of this species, but it was then referred as a variety to the convenient but obsolete receptacle of this genus, U crassus." Say most nearly resembles the preceding, (\ rgpAsW, but may be distinguished by its more triangular elevated outline, and more elevated umltn and ligament It The margin posterior furrow the tuberculated ridge tremity, which epidermis is is is from a fine much narrower the reverse in U cyphiu* and the darker and less polished Inhabits the Ohio and is is nearest the j>osterior ex- specimen in its tributaries The figure Mr PoulsonV cabinet UNIO PLICATl S Plate LXV DESCRIPTION subrhomUudal, very vcntncose; Shell j>ostcrior side x*ith large oblique irregular folds, profound about the umbonial slope, and but slightly impressed on the posterior slope; ligament margin parallel with the base; posterior margin long, slightly oblique, rounded above, and slightly emarginate towards the extremity, which is obliquely truncated inwards; umlx) very prominent, tumid, plicated, nearly terminal; epider- mis blackish or brownish, coarsely white; cardinal teeth deeply sulcated striated; within IT IMicatus l Ixxx tigs 16, IT, 1~ 19 U vkntkicosi 13, fig I, *, U ovatub, Var I mi Jiamcu a h, [dens, Lea in p 4W, I.nm have naturalist, species vi J7, pi p 7f» Vn aans Vert., vol v p Trans Amer So< Philos ., ii< w series, vol pi v < I Silliman's Journal, vol c in IBSERVATH >NS This part copied Barnes' description Mr Say observe-, from closely allied, ovatus, U "tirst nob., and appears distinguished the which to it is v rv to be absolute!) connect- ed by a gradual transition of intermediate varieties The most striking difference appears to b< the more slope ol depressed anterior [posterior] Some old specimens and varieties an more elongated, as The is colour also i- repr< scnted more