174 BRITISH ENTOMOSTRACA. 



prominent teeth. The shell is white, and the surface is 

 grooved longitudinally, the grooves being marked with 

 rows of impressed punctures. 



Approaches near Cytherina scrobiculata oiMimster, 

 \ide Eoetners ' Cytherinen,' &c., in Jahrbuchfiir Mineral., 

 1838, t. 6, f. 1. 



Mab. — Along witli numerous specimens of C. nigrescens^ 

 marked as coming from Boston, Torquay, and Arran, one 

 single specimen of this pretty species was sent to me by 

 W. C. Wilhamson, Esq. 



15. Cythere convexa. Tab. XXI, fig. 3. 



Shell rounded, very convex, and presenting very much 

 the appearance of a small Cypra^a, or Cowrie shell. The 

 surface is covered with numerous small, white, raised dots 

 or points, which are disposed in radiating rows round the 

 cu'cumference, and the whole shell is of a white colour, 

 and translucid. The margin of the shell is somewhat 

 waved. 



Hah. — Torquay, in sand; W. C. Williamson, Esq. 

 Tenby, in sand, T. R. Jones, Esq. 



Genus 2 — Cythereis. 



Cytiiekeis, T. R. Jones, Entoraost. of Cretac. Eormat., 1849. 

 Cythere, Munster, Jahrbuch fiir Mineralogie, 1830. 



— Cornuel, Mem. Geol. Soc. Eraiice. 

 Cythekina, Roemer, Jahrbuch, &c., 1838. 



— Re/iss, Verstein. Bohni. Kreideform. 



— Williamson, Transact. Manch. Lit. Soc. 

 Cypkidina, Bosquet, Mem. Soc. Roy. Liege, 1847. 



Animal unknown. Carapace valves or shell of an 

 almost regular oblong shape, the dorsal and ventral mar- 

 gins lying nearly parallel to each other. Surface of a 

 very irregular appearance, being wrinkled, ridged, and 

 beset with tubercles, and crenulated or strongly toothed 

 on the margins. 



