CRYPTOPLAX. 



483 



Species of Acanthochites. 



astriger, Reeve, 

 castaneus, Couth. 

 cancellatus, Adams and 



Reeve. 

 coarctatus, Soic. 

 discrepans, Broivn. 

 ecliiuatus, Tiles. 

 fascicularis, Linn. 

 formosus, Adams and Reeve. 

 Garnottii, Blainv. 



grauatus, Reeve. 

 bastatus, Sow. 

 laqueatus, Reeve. 

 porphyreticus, Reeve. 

 scutiger, Adams and Reeve. 

 spiculosus, Reeve. 

 strigatus, So7v. 

 violaceus, Quoy and Gaim. 

 Zealandicus, Quoi/ and 

 Gaim. 



Genus CRYTOPLAX, Blainville. 



Body vermiform, thick. Mantle spinulose, encircled 

 with a series of setigerous pores. 



Shell with the valves sub-internal, the three or four 

 anterior continuous, the others interrupted externally by 

 bridges of the mantle ; the exposed part linear, lan- 

 ceolate, elongate. 



8yn. Chitonellus, Lam. Chitonella, Desh. Chito- 

 niscus, Herrm. Ametrogephyrus, Midd. 



Ex.- C. fasciatus, Quoy and Gaimard, pi. 55, fig, 

 n, 6, a. 



The valves in this genus are deeply immersed in 

 the thick, fleshy mantle, the four anterior being con- 

 tiguous, the posterior distinct, gradually becoming nar- 

 rower and diminishing in size. The plate of insertion of 

 the anterior valve is four-lobed, those of the middle and 

 hinder ones entire and thick. The species enjoy consi- 

 derable powers of locomotion compared with other genera 

 in the family. 



