52 NEW UNIONID.E OF THE 



point of tlie abdominal sack only/'' Palpi very large, subelliptical and united nearly 

 half way down the posterior edges. Mantle rather thin, a little thickened above the 

 lower edges. Branchial opening with papillae on the inner side, a row of which latter, 

 diminished in size and wider apart, extends round the basal margin. Anal opening 

 small, with small papillae on the inner edges. Super-anal opening very long, edges 

 sharp, united at the lower part. Anus crenulate on the edge. The mass seems as if 

 it had been whitish, but the specimens have been so long in alcohol that they have 

 become brownish and discolored. The ova were in the branchial uterus, but not de- 

 veloped so as to give the embryonic form. 



Remarks. — There were many specimens in the collection made by Dr. Berlandier, 

 which was purchased by Lieut. D. N. Couch, U. S. A., and liberally presented to the 

 Smithsonian Institution. This species is near to Tecomatensis (nobis), but is not quite 

 so oblique. The young are nearly quadrate and some are beautifully furnished with 

 green rays over a yellowish ground. The description is made from an adult, and they 

 are usually dark brown with a few obscure rays. Some of the young have a carina 

 rising almost into a wing. There are two or three minute undulations at the tips of 

 the beaks. In the left valve the teeth have a disposition to be tripartite. It is pro- 

 bable this species may be found in Texas also. I have peculiar pleasure in dedicating 

 this fine shell to the late Dr. Berlandier, who many years since devoted much time, 

 with great success, to the Natural History of Northern Mexico. I am greatly 

 indebted to the liberality of the officers of the Smithsonian Institution, for the privi- 

 lege of describing this and many other new forms in this collection. 



Unio Saladoensis. pi. 65, fig. 195. 



Testa lajvi, obovata;, inflata, insequilaterali, postici et antice rotundata ; valvulis subtenuibus, antice paulis- 

 per crassioribus ; natibus prominulis, laevibus; epidermide luteo-oliva, polita radiataque; dentibus 

 cardinalibus parvis, lamellatis, obliquis ; lateralibus sublongis; lamellatis aubcurvisque ; inargarita 

 CEcruleo-alba et iridescente. 

 Shell smooth, obovate, infiated, inequilateral, rounded behind and before; valves 

 rather thin, slightly thicker before ; beaks slightly prominent, smooth ; epidermis yel- 

 lowish olive, polished and rayed; cardinal teeth small, lamellar and oblique; 

 lateral teeth rather long, lamellar and somewhat curved ; nacre bluish white and 

 iridescent. 



Proe. Acad. Nat. Sci. I860, p. 305. 

 Hah. — Rio Salado, New Leon, Mexico. L. Berlandier, M. D. 

 Cabinet of the Smithsonian Institution. 

 Diam. -5, Length -8, . Breadth 1-2 inch. 



Shell smooth, obovate, infiated, inequilateral, rounded behind and before; substance 

 of the shell rather thin, slightly thicker before ; beaks slightly prominent, smooth 



*Four specimens since received from Prof. Forshey have no opening at the end of the abdominal sack like 

 those from Matamoras. 



