﻿AND SPECIES OF THE FAMILY UHIONIDJE. 291 



Unio Housei. P1.-23, fig 3. 



Testa bialata, lsevi, triangular!, compressa, valde inaequilaterali, postice obtuse angulata ; valvulis sub- 

 crassis ; natibus prominulis ; epidermide fusca ; dentibus cardinalibus lamellatis ; lateralibus praelongis, 

 lamellatis subcurvisque ; margarita salmonis colore tincta. 



Shell with two wings, smooth, triangular, compressed, very inequilateral, obtusely 

 angular behind ; valves rather thick ; beaks somewhat prominent; epidermis brownish ; 

 cardinal teeth lamellar ; lateral teeth very long, lamellar and somewhat curved ; nacre 

 salmon colored. 



Proc. Acad. Nat. Sci. Vol. 8, p. 92. 



Bab.— Siam. S. R. House, M. D. 



My cabinet, cabinet of W. A. Haines, New York, and Dr. Ingalls, Greenwich, N. Y. 

 Diam. 1*3, Length 3-8, Breadth 4-2 inches. 



Shell with two wings, connate before and behind, smooth, triangular, compressed, 

 very inequilateral, rounded before and obtusely angular behind; substance of the shell 

 rather thick ; beaks rather prominent, with a few very small undulations ; ligament 

 rather long and concealed ; epidermis greenish brown with two lines in the posterior 

 slope, obscurely rayed, smooth and shining ; umbonial slope obtusely angular ; marks 

 of growth distant and indistinct ; cardinal teeth long, lamellar, oblique and double in 

 both valves, but more defined in the right ; lateral teeth long, very lamellar, slightly 

 curved and joined to the cardinal tooth ; anterior cicatrices distinct, the larger one 

 having a deep sinus on the superior part ; posterior cicatrices very indistinctly marked, 

 confluent; dorsal cicatrices well marked in the cavity of the beaks; cavity of the 

 shell very shallow ; cavity of the beaks very shallow and obtusely angular ; nacre 

 delicately salmon colored and iridescent. 



Remarks. — This belongs to a natural group of symphynote species of which IT. 

 delpldnus may be considered the type. It is, however, not so wide, nor has it so high 

 a wing posteriorly. It differs also in the teeth, the cardinal teeth being more lamel- 

 lar and divided into two or more parts, while those in the delpldnus are flattened and 

 crenulate or granose. The lamellar teeth of delphinus are nearly straight, or entirely 

 so, while those of Housei are more or less curved. The specimens were all more or 

 less injured, and particularly in the wings. 



I owe this, with many other species from Siam, to the kindness of Mr. W. A. 

 Haines, who obtained them from Dr. House, now a resident of the city of Bangkok, 

 and to the latter gentleman I dedicate this fine species with pleasure. 



Unio luteus.* PI. 24, fig. 4. 



Testa lsevi, elliptica, innata, subsequilaterali, postice obtuse angulata ; valvulis crassis ; natibus subpromi- 

 nentibus; epidermide lutea, polita ; dentibus cardinalibus crassis brevisque; lateralibus brevis, sub- 

 crassis subrectisque, margarita alba et iridescente. 



* This was printed, by typographical error, in the Proceedings, Vol. 8. p. 93. lutens instead ot'lHteiis. 



