384 MR. G. S. BRADY ON NEW OR IMPERFECTLY 



1. Cythereis batei, n. sp. (PI. LX. fig. 8, a-d.) 



Valves oblong, quadrilateral, compressed. Anterior margin elevated, rounded, irre- 

 gularly waved and dentate. Posterior extremity narrowed, produced inferiorly into a 

 thin, rugose lamina which, at its edge, is broken into irregular dentations. Dorsal and 

 ventral margins nearly straight. Viewed from below, the carapace exhibits a central 

 quadrilateral portion, traversed in the median line by a broad keel (the hinge-margins) 

 which projects considerably before and behind, forming broad, truncate prolongations. 

 The lateral surface of each valve is marked by a strong longitudinal median ridge, 

 which is puckered and dentate. 



Length 3-3- in. (78 mm.). 



Hab. Levant (sponge-sand). 



I have pleasure in naming this very distinct species after ]\Ir. C. Spence Bate, of 

 Plymouth. 



2. Cythereis cristatella, n. sp. (PI. LXL fig. 1, a-d.) 



Carapace compressed, oblong, bearing a central longitudinal eminence. The margins 

 are much elevated, particularly at the extremities. The extremities are well rounded 

 (the anterior being a little the broadest), and at their lower margins are slightly ser- 

 rated. The dorsal and ventral margins are sinuated in the middle, and about the 

 anterior third of the dorsal edge there is a marked angular elevation. Dorsal outline 

 compressed, hastate, with a broad, projecting keel. Surface smooth. 



Length ^- in. (-63 mm.). 



Hab. Australia. 



3. Cythereis subcoronata, Speyer. (PI. LX. fig. 9, a-e.) 



Cythere subcoronata, Speyer, Ostrac. der Cassel. Tertiarbild. p. 38, t. 4. figs. 9, 10. 



Valves oblong oval, compressed, much elevated in the centre, twice as long as broad. 

 Dorsal and ventral margins straight or but slightly convex. Anterior margin broad 

 and somewhat flattened. Posterior margin rounded, armed with about nine strong 

 teeth, which increase in size towards the ventral margin. Dorsal profile elongate oval, 

 very prominent in the middle, tapering rapidly to the extremities. Surface of the valves 

 smooth and polished, rising to a peak near the middle of the ventral border. A broad 

 flattened border encircles the central elevated portion, and is beset at intervals with 

 strong square teeth. Within the ventral margin is a row of rounded tubercles, five, 

 six, or more in number, and the dorsal margin is irregularly armed with blunt, square 

 teeth. End view pyramidal. 



Length -^ in. (84 mm.). 



Hab. Smyrna (shallow water). Three or four specimens. 



In surface-ornament this does not exactly agree with Speyer's figures of C. subcoro- 



