184 CHITON. 



C. LYRATUS Sowerby. PL 31, figs. 35, 36. 



Shell oval, smooth ; back subangulated ; lateral areas subelevated, 

 smooth ; central areas longitudinally lirate at the sides ; girdle broad, 

 minutely scaly. Length 37, breadth 15 mill. (Sowb.) 



This shell is so thin as to be nearly transparent ; it is smooth, 

 rather angulated in the center, the lateral areas smooth, slightly 

 elevated, the central areas marked with faint longitudinal ribs. The 

 margin is covered with regular, minute scales. The general color 

 is drab, variegated with brownish concentric lines at the sides and 

 reddish-brown dorsal bands on some of the valves. (Sowb.) 



Habitat unknown. 



Chiton lyratus SOWB. in Charlesworth's Mag. of Nat. Hist. 1840, 

 p. 293 ; Conchol. Illustr., f. 126. REEVE, Conch. Icon... f. 110. 



This shell should be compared with caiim-icnsis Orb. and c?w- 

 X/////7/X Reeve. 



Carpenter has described a C. semilcevis in MS. from Cumingian 

 specimens of unknown locality. It will probably prove to be a form 

 of the above species. 



Reeve reports C. lyratus from Prince Island, West Africa, under 

 stones. 



C. DISSIMILIS Reeve. PL 37, fig. 11. 



Shell oblong-ovate ; terminal valves and lateral areas longitu- 

 dinally grooved, smooth in the middle ; variegated with reddish- 

 brown ; ligament granosely coriaceous, tessellated. Approximating 

 in some measure to the C. tiilipa. (Reeved) 



Habitat unknown. 



C. dissimilis REEVE, Conch. Icon., t. 25, f. 170 (May, 1847.) 



Reeve s description does not correspond very well with his figure ; 

 and the species will probably prove to be the same as C. canariensis 

 Orb. 



Carpenter notes that in Reeve's type specimen the whole surface 

 is conspicuously quincuncially granulated. The anterior valve has 

 9, central 1, posterior valve 13 slits; teeth sharply pectinated. It 

 measures, length 18, breadth 9 mill.; divergence 90. 



C. CANARIENSIS d'Orbigny. PL 34, figs. 77, 78, 79. 



Shell oblong ; carina smooth, central areas of the valves longitu- 

 dinally sulcated, lateral areas smooth ; ends smooth ; margin 

 granulate-scaly. Length 24, width 12 mill. (Orb.) 



