218 



rotundato ; latere siphonali duplo longiore, triangular!, subad- 

 scendente, truncate ; margine dorsali recto ; margine ventrali 

 arcuato, sub-pendulo : interior deaurata. Long, f ; alt. I poll. 

 Hah. Puget Sound. 



It is with some doubt that I separate this from 0. hyalina ; 

 but if its gilded nacre, its dusky colored, very numerously 

 folded epidermis, and the ventricose, pouched form of the pos- 

 terior basal portion prove constant, there can be no room for 

 doubt. 



OsTEODESMA Brasiliensis (Couthouy, MS.) Testa fragilis, 

 elongato-ovata, antice ventricosa et truncata, postice compressa, 

 concentrice undulata, epidermide flavicante induta ; umbonibus 

 ante-medianis, tumidis, approximatis ; margine dorsali fere rec- 

 tilineari ; margine ventrali arcuato: interior margaritacea : ossi- 

 culum parvum, oblongum. Long. 1^; alt. f poll. Hah. Rio 

 Janeiro. 



Its elongated, leguminous form, and its large size, plainly 

 characterize it. 



Amphidesma croceum. Testa maxima, crassa, calcarea, ine- 

 quivalvis, subcircularis, postice hiantula et sub-truncata, liris 

 concentricis reflexis interdum divarlcatis arata, radiatim stri- 

 ata ; umbonibus sub-medianis, eminentibus, acutis, contiguis : 

 intus crocea ; cardo validus, fovea ligamentali ampla, profunda ; 

 dentibus rosaceis. Long. 3^ ; alt. 3^ ; lat. 1^ poll. Hah. 

 Callao ? 



Very distinct from all other described species, unless it may 

 be A. solidum, Gray ; from comparison with his description 

 alone, this must be different. 



Erycina (Poronia) ovata. T. parva, alba, nitida, concen- 

 trice striata, ovato-ventricosa, inequilateralis; margine cardinal! 

 arcuata, umbonibus parvis, antemedianis; margine ventrali parum 

 arcuata; latere antico truncate ; latere postico rotundato ; valvss 

 dextrse dente cardinal! erecto, bifido, fovea ligamentali parva ; 

 V. s. dente integro ; intus alba. Long, /g- ; alt. ^ ; lat. } poll. 

 Hah. Sandwich Islands. 



Differs from the succeeding species in its smaller size, more 

 inequilateral, ovate-ventricose form, shining surface, and delicate 

 fringe. 



