1917.] NATURAL SCIENCES OF PHILADELPHIA. 195 



Length of right valve 23, alt. 23, diam. 3.5 mm. 



Type No. 2780, A. N. S. P. 



The collection contains five left and si.\ right valves. 



Crenella diuturna n. sp. 



CreneUa divaricata d'Orb., Gabb, Trans. Amer. Philos. Soc, XV, 1873, p. 252. 



The shell is small, rounded-oval, resembling C. duplinensis Dall, 

 but differing by the somewhat greater inflation, and by having 

 regularly spaced, concentric threads over the rather fine divaricate 

 ribbing. Hinge much more delicate than in C. divaricata (Orb.); 

 crenulation of the valve-margins short and very weak. 



Length 1.85, alt. 2.3, diam. 1.5 mm. 



The line of divarication is well out of the median line. Several 

 A^alves agree in characters of form and sculpture. 



CreneUa rota n. sp. 



The shell is rather convex, almost circular, having rather fine low 

 ribs divaricating at a small angle from the median line, and crossed 

 by numerous weak concentric threads. Valve margins very strongly 

 crenulated. 



Length 1.8, alt. 1.95, diam. 1.4 mm. 



Type No. 2753, A. N. S. P. 



Distinguished by its subcircular outline. 



Cuspidaria ornatior n. sp. 



Neaera ornatissima d'Orb., Gabb, Trans. Amer. Philos. Soc, XV, p. 248. 



The shell resembles C. ornatissina (Orb.), but has much more 

 numerous radial ribs, 22 in the type; on the anterior half they are 

 subequal, evenly spaced and blunt. Concentric wrinkles along 

 growth-lines are rather well developed in places. 



Length 4.75, alt. 2.7 mm. 



T>T3e No. 2790, A. N. S. P. There are broken valves indicating a 

 considerably larger size. 



Cuspidaria gabbi n. sp. 



Neoera alternata d'Orb., Gabb, Trans. Amer. Philos. Soc, XV, p. 248. 



The shell is plump, with elevated, nearly central beaks, much 

 attenuated behind, rostrate, the upper margin sloping and nearly 

 straight before, very deeply concave behind the beaks. Basal 

 margin is incurved posteriorly. There are about 30 radial ribs, 

 the posterior one largest and a little more widely separated from its 

 neighbor; following 4 or 5 ribs of intermediate size, the rest smaller, 

 subequal, and not reaching nea ly to the beaks. 



Length 8, alt. 5.4, semidiameter 2.5 mm. 



Type No. 2791, A. N. S. P. 



