SCHlZOCHITOJf. 477 



In this genus the lamina of insertion of the anterior 

 valve is few-lobed, that of- the posterior somewhat obso- 

 lete, entire, and receding, and that of the middle bi-lobed. 

 Only a single species, from the coasts of Chili, has been 

 hitherto discovered. The plates of insertion are very 

 similar to those of Plaxiphora. 



Genus LORICA, H. and A. Adams. 



Mantle-margin very densely covered with small, smooth, 

 ovate, imbricate scales, the posterior margin fissured. 



Shell with the valves broad, transverse, external; the 

 hinder valve small, with the apex terminal, produced, and 

 notched on its hind lower edge. 



Syn. Aulacochiton, Shuttleicorth. 



Ex. L. cimolia. Reeve, pi. 54, fig. 5. 



The plate of insertion of the anterior valve in Lorica 

 is few-lobed, that of the posterior deeply emarginate, and 

 obsoletely lobed, and that of the middle valves bi-lobate. 

 The squamose mantle distinguishes this genus from 

 Schizochiton and Mopalia, and the deep notch in the 

 centre of the hind margin of the posterior valve from 

 Lophyrus. 



Species of Lorica. 

 cimolia, Reeve. volvox, Reeve. 



Genus SCHIZOCHITON, Gray. 



Mantle-margin broad, horny, sparsely covered with 

 small, chafF-like, and cylindrical curved scales, the poste- 

 rior margin deeply fissured. 



