85 



CORBULA nitida. 



TAB, CCCLXIL— Figs. I, 2, and S. 



Spec. Char. Ovate, subtrigonalj equilateral, 



gibbose^ anteiiorly traiicated^ smooth ; valves 

 nearly equaL 



A THIN sliell, most gibbose towards the beaks^ wMcIs 

 are somewhat produced ; the young- individuals are 

 rather pointed on the slides ; the old ones oval, "vyith a 

 small truneature anteriorly ; the surface is smooth^ often 

 shining', and the valves very nearly equal : length rather 

 more than half the width. 



Very small, not exceeding three-tenths of an inch iia 

 width : the almost perfect equality of the valves is re- 

 jnarkable, but the form of the hinge is exactly that of the 

 genus Corbula^ from which it cannot conveniently h® 

 separated. 



First observed with the following", by Professor Sedg- 

 wick, in several parts of the Isle of Wig-ht, below the 

 upper fresh-water formation. 



Figs. 2 and 3 are magnified repFesentatioDS. 



CORBULA cuspidata. 



TAB. CCCLXIL— FiV^. 4, 5, and 6. 



Spec. Char. Transver&ely oblong, tumid, in- 

 eqiiivalved, subequilateral ; anteriorly ca- 

 rinated and cuspidated; lower margin of the 

 left valve expanded and inflected^ 



j\ THICK blunt-edged shell, whose anterior side is 

 obliquely truncated, and defined by a ridge that ends iu 

 a projecting point ou tlie margin : the lip-formed edge c»f 



