284 MANUAL OF THE MOLLUSCA. 



Synonyms, Schizo- chiton, Corephium, Plaxiphora, Onycho- 

 chiton, Enoplo-cMton, Gray. 



Distribution, West Indies, Cape Horn, Falklands, Africa, 

 Philippines, Australia, New Zealand, Valparaiso. 



Mopcdia, Gray. C. Hindsii. Border hairy. 



Distribution, West America, Falkland Islands. 



Katharina, Gray. C. tunicatus. Mantle covering all but 

 the centre of the plates. 



Distribution, New Zealand, West America. 



Cryptochiton, Gray, " Saw-dust chiton." 0. amiculatus. 

 Valves covered with scaly epidennis. 



Synonyms, Crj^ptoconchus, Sw. Amicula, Gray. 



Distribution, California. New Zealand. 



Acanthochites, Leach. C. fascicularis. PI. XI.. Fig. 30. 

 Border ornamented with tufts of slender spines, opposite the 

 plates. 



Distributix)n, Britain, Mediterranean, New Zealand. 



Chitonellus, Lam. C. fasciatus, Quoy. PI. XL, Fig. 31. 

 Border velvety ; exposed portion of the plates small, distant ; 

 apophyses close together. The dentition of chitonellus is repre- 

 sented in Fig. 121. 



Distribution, 10 species. West Indies, West Africa, Philip- 

 pines, Australia, Pacific, Panama. The chitonellce are found in 

 fissures of coral rock. (Cuming.) 



Fossil, Carb. Scotland. 



Gryphochiton, Gray, C. nervicanus. 



Ilelminthochiton, Salter, 1847. H. Grifiithii, Salter^ Geological 



Fig. 121. Chitonellus. Tasmania. (Wilton.) 



Journal. Plates sub-quadrate, not covered bv the mantle : 

 apophyses widely separated. 



Fossil, Silurian. Ireland. 



JSrownia, Candoi, D'Orbigny, 1803. A minute discoidal 

 shell, associated with Helicoplilegma in the first instance, but 

 distinguished by the serrated keels on its whorls, and lateral 

 notches to the aperture. Cuba. 



Calcarella, spinosa, Souleyet, 1850. 



Shell sub-globose, dextrally spiral, horny, pellucid, with three 

 acutely serrated keels ; aperture thickened, entire. Lateral 3 



