ON THE NEW GENUS OF BIVALVE. 



CURVIROSTRUM STRIATUM. 



By PROFESSOR BUCKMAN, F.G.S., F.L.S., S^-c, ^-c. 



nIIIS shell belongs to the family Arcadm, which is thus 

 distinguished by Dr. Carpenter : — 



Shell regular, equivalve, with strong epidermis, 

 hinge with a long row of similar, comb-like teeth, muscular 

 impressions sub-equal, structure corrugated with vertical tubuli 

 in rays between the ribs or stria. 



The annexed wood-cut shows the left valve of a large speci- 

 men. 



no. I.— otmyiEosTEUM steiatitm. 



The Genus is distinguished by an abnoimally produced and 

 incurved umbo. 



rw II.— UMBO or cubvieosteum. 



