110 ISCHNOCHITON. 



C.j'i'iiinosm OLD. Proc. Bost. Soc. N. H. ii, p. 144, July 1846; 

 Otia Conch, p. 5, 242; U. S. Expl. Exped. p. 316, f. 419. 

 ROCHEBRUNE, Polyplax. Cap Horn, p. 141. lachnochiton j>rn!n<>- 

 8W CPE. MS. p. 77* 103. 



Carpenter seems to consider this the same as caribbceorum and 

 xti'iolatus; but the specimen before me is too worn to enable me to 

 decide. 



I. REGULATUS Sowerby. PL 21, figs. 53-57. 



Shell oblong, rather smooth, olivaceous varied with white ; front 

 valve, lateral areas and posterior valve concentrically undulately 

 wrinkled ; central areas smooth, wrinkled at the margins. Length 

 20, breadth 10 mill. Girdle granose. (Sowb.} 



Puerto Portrero and Inner Lobos Id., Central America, under 

 stones at low water. 



Chiton rugulatus SOWB., P. Z. S. 1832, p. 58 ; Conchol. Illustr. f. 

 42, 78, 143, 144 ; Beechey's Voyage, Zool. p. 150, pi. 41, fig. 18. 

 REEVE, Conch. Icon. t. 19, f. I 1 8 ; t. 20, f. 128, l33.Ic/uH>rIuton 

 rugulatus CPR., MS. 



Carpenter describes the interior and girdle from the type speci- 

 men, thus: Posterior and anterior valves having 9, central valves 

 1 slit; teeth solid ; eaves moderate; sinus wide, flat. Girdle closely 

 imbricated with moderate sized solid scales, scarcely striated. 



It is very like striotatus but having stronger sculpture. It goes 

 through all the color variations of longicymba. The scales seem to 

 be smooth, but here and there are slight striolations from the dried 

 skin. 



I. CATENULATUS Sowerby. PI. 21, figs. 47, 48. 



Shell long and narrow, elevated, arched, the jugum rounded. 

 Girdle smooth, broad, thin, with imbricating striated scales. Mucro 

 central, elevated, the posterior slope somewhat concave. Central 

 areas sculptured with very close parallel lirulas, which pass into 

 wrinkles on the lateral areas, which are swollen. End valves con- 

 centrically wrinkled. Interior : posterior valve having 10, central 

 1, anterior valve 9 slits; teeth long, sharp, thin ; eaves moderate, 

 not long, but well developed ; not spongy. Sinus broad, deep, 

 smooth, channelled. Length 17, breadth 7 mill. ; divergence about 

 102. (<>-.) 



Inner Lobos Island, Peru. 



