186 ' NEW UNIONID^, MELANID^E, ETC., 



Proc. Acad. Nat. Sci., 1856, p. 80. 



Hah. — Sacramento River, California, Dr. Trael# ' 



My cabinet and cabinet of Dr. Trask. 

 Length -33, Breadth -25, Height -16 inch. 



Remarlcs. — I received four specimens from Dr. Trask of this interesting shell, which 

 came with Lymnece, &c., from Sacramento River. The exact part Dr. T. does not men- 

 tion. It is remarkable for its close resemblance to the young of Patelloida testudinaria, 

 Lea, [Patella amcena, Say). The maculations are very much of the same character, 

 but not so distinct, and they are more disposed to run into zigzag forms. The outline 

 and position of the apex are very nearly the same. It differs very much from Ancy- 

 lus Nuttallii, Hald, from Oregon, (slip published March, 1841). That species is 

 smaller, more ovate, without maculations, and has the apex much nearer to the poste- 

 rior margin. It also differs from A. crassus, Hald., from Oregon, (Monog. No. 7, page 

 14), having the apex more medial, having maculations, and in other characters. In 

 the four specimens before me there is some difference in form and color. • Two of 

 them are much flatter than the others, and one is quite dark brown, relieved with 

 indistinct white elongate spots. This species is so much like the small marine 

 Patellae, that it has not been without some hesitation that I have placed it in the 

 genus Ancylus, particularly as I am not informed from what part of the Sacramento 

 these were taken. The soft parts not having accompanied the specimens, I have not 

 had the advantage of that guide. The cicatrix of attachment, however, is plainly 

 impressed, and opens on the right side. 



Amnicola Currieriana. pi. 24, fig. 118. 



Testa ls3vi, suborbieulari, tenui, luteo-oornea ; spira depressa; suturis impressis ; anfraotibus quaternis, 

 superne geniculatis ; apertura subconstricta, semi-lunata, intus diaphana ; labro acuto, expanso, 

 retrorso ; columella incrassata, lata at impressa. 



Shell smooth, suborbicular, thin, yellowish horn-color ; spire depressed ; sutures 

 impressed ; whorls four, geniculate above ; aperture subconstricted, half-moon shape, 

 transparent within ; outer lip acute, expanded, bent backward ; columella thickened, 

 broad and pressed in. 



Operculum ovate, pale horn-color, thin and transparent, with the polar point on the 



left edge near the base. 



Proc. Acad. Nat. Sci., 1863, p. 156. 



Hah. — Huntsville, Alabama, W. H. De Camp, M, D. 



My cabinet and cabinet of A. 0. Currier. 

 Diam. -14, Length -13 inch. 



Remarks. — This little species differs from all other Amnicolce whiich I have seen in 

 the broad deposit of the columella, particularly in the middle, where it covers the 



