CYTHERE. 291 



shaped; valves smooth, glaucous, bright-orange. A very 

 minute species. 



Hab. Berwick Bay. 



Cythere nigrescens, Baird. — Shell gibbously ovate, 

 hinder end with a sharp point ; valves smooth, of a dirty- 

 black colour. 



Hab. British coasts. 



Cythere minna, Baird. — Shell elongate-ovate, pointed 

 behind ; valves white. The largest British species met with 

 by Dr. Baird. 



Hab. Deep water near Shetland, where it w r as dredged 

 by Mr. M' Andrew. 



Cythere inopinata, Baird. — Shell oblong, ovate, white, 

 with a slight orange-coloured mark on upper edge ; each 

 valve with a gibbous projection about the middle. 



Hab. Small pond between Hanwell and Southall, Mid- 

 dlesex. Dr. Baird called this " inopinata " — unexpected — 

 from its curious habitat, it being the second species only re- 

 corded as inhabiting fresh-water. It is a very small species, 

 and always creeps at the bottom. 



Cythere angustata, Munster, sp. — Shell oval-oblong, 

 pale yellow-surface polished ; when seen under the micro- 

 scope it is covered with small asperities. 



