CYTHEREIS. 
293 
Gen. 158. CYTHEREIS, Rupert Jones . 
Yalves of carapace oblong, dorsal and ventral margins 
parallel to each other ; surface irregular, ridged, tubercular ; 
margins toothed or crenulated. Animal unknown ; probably 
like Cythere . 
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. 
Bairhia subheltoidea, 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 
