Zoological Society. 133 



ftt Margin smooth ? ; lateral area very distinct. 



A. ? gigas. Ch. gigas, Gmel. Cape of Good Hope. 

 A. ? truncata. Philippines. 



4. Schizochiton. 



Valves elongate, subcordate, narrow ; lateral area short, distinctly 

 defined ; the hinder valves large, with a subposterior superior apex 

 and a deep notch on its hinder lower edges, and the plate of insertion 

 small, with a few oblique notches, scarcely pectinated. Mantle 

 broad, covered above with small chaff-like scales, deeply notched 

 behind. 



Schizochiton incisus. Chiton incisus, Sow. Philippines. 



5. Corephium. 



Valves broad ; wing of insertion of the anterior valve lobed and 

 pectinated ; the hinder valve oblong, with a subcentral, subposterior, 

 not produced apex ; the edge of insertion distinct, not lobed on the 

 sides, with a single nick behind, and slightly denticulated ; mantle 

 spinose. 



C. echinatus. Chiton echinatus, Barnes. C. tuberculiferus, Sow. 

 Ch. spiniferus, Frembly; Sow. C. Illust. f. 47, young. 



6. Plaxiphora. 



P. Carmichaelis. Chiton Carmichaelis, Gray, Spic. Zool. Ch. 

 albidus, Blainv. 547. Ch. raripilosus, Blainv. 547. Ch. costatus, 

 Blainv. 547. Ch. biramosus, Quoy, Voy. Astrol. t. 74. f. 12, 16. 

 Ch. setiger, King, Z. J. v. 338; Sow. Conch. III. f. 17. Ch. Frem- 

 blii, Brod. P. Z. S. 1832, 28 ; Sow. Conch. III. f. 2. Ch. setosus, 

 Sow., Beechey Voy. Terra del Fuego. 



See also Ch. setosus, Sow. C. III. f. 19 ? 



7. Onithochiton. 



O. Gaimardi. Chiton Gaimardi, Blainv. 546. 



O. hirtosus. Chiton hirtosus, Blainv. 546. 



O. undulatus. Ch. undulatus. Van Diemen's Land. 



8. Enoplochiton. 



E. niger. Ch. niger, Barnes. Ch. Coquimbensis, Frembly. Co- 

 quimbo. 



The valves become very much eroded. 



9. Mopalia. 



Valves broad, transverse, depressed ; margin of insertion moderate ; 

 the hinder valve with a rounded lobe on the hinder edge ; mantle 

 moderately broad, bristly above, narrow behind. 



* Margin moderately wide in front. 



M. Hindsii. Ch. Hindsii. West coast of America. 

 M. Simpsonii. Ch. Simpsonii, Gray. Brit. Mus. 



