1316 S['\Tn.\ 



Spatha roinndaia vox Martens, Besch.. 1897, p. 242, fig. d. 

 Spatha ruhens var. rotundata Germ at \. Arch. Zoo!. Exp. et 



Gen.. (5). I, TQ09. p. 55. 



The above measurements will show that this species is quite 

 variable in size and form, as all of them are from adult speci- 

 mens. There is much variation in the color of the nacre, 

 which in some shells is quite dark, while it is light in others. 

 A young specimen 70 millimeters long, which came with other 

 shells in the National Musemn from the Nile, has bluish-white 

 nacre with scarcely a tint of purple. 



Germain, (1. c), considers von Martens' icissiiiaiii and ro- 

 tundata entitled to varietal rank. 



\^v. caiUiaudi von Martens. 



Shell long elliptical or long subrhomiboid. subsolid or solid ; 

 epidermis brownish-red, duller than in the type ; nacre rose- 

 colored or white. 



Length 140. height 94, diam. 49 mm. 



Length 142, height 87. diam. 49 mm. 



Length 97, height 58, diam. 33 mm. 

 Anodonta ruhens Audouin in Savigny, Icon. Moll. Eg., 1827, 



pi. VI T, fig. I. 

 Spatha caUUaudi von Martens, Mai. Bl., XIII, 1866, p. 9. — - 



IiCKELi, L. and S. W. Moll., 1874, p. 259, pi. viii, fig. i. — 



KobeIvT, Icon., new ed,. 11, 1886, p. 27, pi. xlvi, fig. 267. 

 Spatha ruhens var. caiUiaudi Simpson, Syn., 1900, p. 896. 



I have before me a fine specimen of this, said to come from 

 Alexandria. Egypt, which agrees wdth the description and 

 w^ith Jickeli's figure. I am inclined to believe it a mere va- 

 riety of S. ruhens, because T have seen shells of that species 

 with the brown, somewhat roughened epidermis and dark cop- 

 pery nacre and the young shell previously mentioned with the 

 poli.shed epidermis and whitish nacre. 



^^ar. chudcaui Germain. 



"Shell large, subtrapezoidal, slightly elongate, valves quite 

 inflated, very thick and heavy ; dorsal margin convex, slightly 

 ascending ; ventral margin slightly sinuous, meeting the dorsal 



