804 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.xxii, 



"beautiful, granularly striate callus is developed behind the laterals; 

 uacre finely, often bifurcately radiate striate outside the parallel line. 

 Animal unknown. 



t SHISTODESMUS LAMPREYANUS Baird and Adams. 



* UnioiDysiiomia^lanipreyanus, Baird andADAMS,Proc.Zool.Soc. Lond., 1867, p. 491, 



pi. XXVI, figs. 2, 2a.—* SowERBY, Conch. Icon., XVI, 1868, pi. Lxxxvii, fig. 



469.—* Heude, Couch. Fluv. Nank., VII, 1883, pi. Lix, figs. 114, 114a, Uih.— 

 - ^P^TEL, Conch. Sam., Ill, 1890, p. 156. 

 Margaron ( Unio) lamprenanus Lea, Syn., 1870, p. 30. 



SHISTODESMUS SPINOSUS Simpson. 



Unio restita8^^air. fi, Heude, Concb. Fluv. Nank., VIII, 1883, pi. lix, fig. 115. ' 



Genus GIBBOSULA Simpson, 1900. 



(Type, My a crassa Wood.) 



Shell very solid, inequilateral, triangular-elliptical, arcuate, pointed 

 behind, with a low, well-marked posterior ridge; beaks rather high; 

 beak sculpture not seen ; posterior two-thirds of the shell covered with 

 somewhat radiating corrugations and nodules; posterior slope having 

 strong subradial folds; epidermis dark; hinge plate very wide; pseudo- 

 cardinals not large, stumpy, rough; laterals very heavy, club shaped; 

 beak cavities enormously deep and compressed; anterior cicatrices 

 rather shallow, rough in the bottom ; posterior cicatrices deep and dis- 

 tinct; a strong rib runs from the front part of the beak cavity toward 

 the posterior base; nacre whitish. 



Animal unknown. 



t GIBBOSULA CRASSA Wood. 



"*. Mya crassa Wood, Geu. Conch., 1815, p. 106, pis. xx, xxi ; - * Ind. Test., 1825, p. 12, 

 pi. II, fig.28&; *Ind. Test. Rev., 1856, p. 16, pi. ii, fig. 28. 



* Mya ponderosa Dillwyn, Dill. Cat., I, 1817, p. 51. 



'* Margarita Unio ponderosus Lea, Syn., 1836, p. 14; 1838, p. 14. 



"" Unio ponderosus YiA^U£Y, Test. Moll., 1842, p. 177; 'Biv. Shells, 1843, p. 177. — 



■' Catlow and Reeve, Conch. Nom., 1845, p. 63. — * H. and A. Adams, Geu. 



Rec. Moll., II, 1857, p. 497. 



* Margaron {Unio) ponderosus Lea, Syu., 1852, p. 21; 1870, p. 32. 



China. 



Genus CUNEOPSIS Simpson, 1900. 

 (Type, Unio celtiformis Heude.) 



Shell solid, elongated, wide and truncate or rounded in front, taper- 

 ing to a point behind; often twisted on its axis and curved to the right 



1 Heude made this a variety of his Unio vestitus (which I have placed in Qitadrula. 

 I am satisfied that this is a Shistodesmus and distinct from lampreyanus, as it seems 

 to have spines instead of knobs. His name vestitus is preoccupied in Unio by Lea.) 



-The name crassus had been previously applied to a U7iio hy Retzius, but as 

 Wood's species was never placed in Unio under the specific name crassus, his name 

 may be used. 



