CYTHEREIS. 293 



Gen. 158. CYTHEREIS, Rupert Jones. 



Valves of carapace oblong, dorsal and ventral margins 

 parallel to each other; surface irregular, ridged, tubercular ; 

 margins toothed or crenulated. Animal unknown ; probably 

 like Cy there. 



Cythereis Whitei, Baird. — Shell oblong, flat ; margin 

 continued straight to the end ; the centre of each valve with 

 a sharp crenulated crest. 



Hab. Torquay and Tenby, in sand. 



Cythereis Jonesii, Baird. — Shell thick, oblong; narrow 

 end flattened, with seven strong teeth projecting from the 

 end ; centre plane and smooth. 



Hab. Isle of Skye, in sand. 



Cythereis antiquata, Baird. — Shell oblong, very thick, 

 roughly granulated with two or three thick ribs along the 

 centre of the valves ; circumference wrinkled. 



Hab. Isle of Skye, in sand. 



Bairdia subdeltoidea, Munster, sp. ; Rupert Jones. — 

 Has the carapace triangular, gibbous, acute at the extre- 

 mities, smooth or setiferous, and sometimes finely punctate ; 

 right valve smaller and more angular than the left. This 



