196 PROCEEDINGS OF THE ACADEMY OF [April, 



Near Sphena alternata Orb., but the dorsal border is much more 

 concave behind the beaks. 



Crassatellites (Crassinella) microdelta n. sp. 



Gouldia martinicensis d'Orb., Gabb, Trans. Amer. Philos. Soc, XV, p. 252. 



The shell is subtriangular, the anterior and posterior slopes forming 

 a right angle, basal margin strongly curved; lunule and escutcheon 

 narrow, flattened, smooth; sculpture of strong, regular, rounded 

 concentric ribs, about 19 visible in a lateral view of the valve, seven 

 in 1 mm. measured upward from the basal margin. 



Length 2.6, alt. 2.5, semidiameter 0.6 mm. 



Type No. 3229, A. N. S. P. 



According to the figures, Orbigny's Crassatella martinicensis has 

 coarser, more widely spaced ribs. There is, however, a recent 

 Antillean species which resembles this Oligocene form closely in 

 sculpture. 



Crassatellites (Crassinella) dolatus n. sp. 



The shell is rather convex, the anterior slope straight, posterior 

 convex; lunule is somewhat sunken and large; -escutcheon narrow. 

 Sculpture of coarse rounded concentric ribs much wider than their 

 intervals, 15 being visible on a valve, five in 1 mm., measured upward 

 from the basal margin. In the valleys very minute crowded radial 

 striae are seen. 



Length 3, alt. 3, semidiameter 1 mm. 



Type No. 3230, A. N. S. P. 



This species differs from the preceding by its much coarser sculp- 

 ture, larger, more distinctly defined lunule, and greater convexity. 



Venericardia aversa n. sp. 



The shell is small, extremely plump, higher than long, with very 

 large, strongly prosogyrate beaks, and no lunule. Sculpture of 18 

 strong tuberculiferous ribs equal to the interstices. Cardinal tooth 

 very high and thin, the socket correspondingly of unusual depth, 

 narrow. The inner margin is very strongly fluted, and there is a 

 pit under the end of each rib. 



Length 12, alt. 12.5, semidiameter 6.3 mm. 



Type No. 3215, A. N. S. P. 



This small species is well characterized by the inflated form (the 

 diameter being about equal to the length), by the long cardinal 

 tooth and deep socket, and the large beaks. Valves of two indi- 

 viduals, right and left, are in the collection. 



