﻿OBOVARIA 



297 



since writing tlie Synopsis are probably not this, but more likel} 

 the dwarf form of O. lens that I have called .var. parva. 



OlJAVARlA NUX n. S. 



Shell rather small, greatly inflated, obovate, solid, consid- 

 erably narrowed and rounded in front, wider and subtruncate 

 behind ; beaks no doubt full and high, but greatly eroded in the 

 only shells seen, placed well towards the anterior end ; poste- 

 rior ridge moderate and above it is a shallow, wide radial de- 

 pression ; base line rounded, quite full behind the middle ; sur- 

 face with a few feeble ridges, otherwise smooth ; epidermis a 

 rich chestnut, very much lighter colored posteriorly and at 

 the base of the shell ; left valve with two triangular pseudocar- 

 dinals and two remote, short, curved laterals, the high arched 

 hinge line narrowed and rounded between the two sets of teeth ; 

 right valve with one strong pseudocardinal, a vestigial tooth 

 each side of it and one somewhat double lateral ; beak cavities 

 rather shallow ; dorsal scars showing in a row under the pseu- 

 docardinals ; muscle scars small, impressed ; nacre whitish. 

 The only specimens seen probably females, having a sulcus 

 behind, such as is found in 0. leibii, and a rather full marsu- 

 pial region. 



Length 40, height 30, diam. 25 mm. 



Tomlbigbee River, Moscow, Ala; Cannisaria Lake, Louis- 

 iana. 



I am exceedingly loath to name a species in this especially 

 difficult group from a couple of specimens, yet the shells T 

 have described will not fit anywhere. The species is perhaps 

 nearest to O. leibii, but it is solider, darker and smoother than 

 that. The smaller of the two shells before me, from Canni- 

 saria Lake. Louisiana, is a female and agrees in all essential 

 characters with the larger shell from the Tombigbee River. 



Orovaria rotulata (B. H. Wright). 



Shell almost circular in outline, solid, inflated, probably hav- 

 ing high beaks, whidi are badly and deeply eroded in the type, 

 with a faint, curved posterior ridge and a small, somewhat 



