ISCHNOCHITON. 115 



Interior whitish ; anterior valve having 10, central 1, posterior 

 valve 9 slits; teeth sharp, thin and smooth ; eaves narrow. 



Girdle narrow, alternately olive-brown and whitish, clothed with 

 very minute, imbricating striated scales. 



Length 82, breadth 5 mill. 



Length 51, breadth 8-1 mill. 



Jamaica (Adams) ; Marco, No Name Key and Key West, Florida 

 (Hemphill). 



Chiton papillosus AD., Proc. Bost. Soc. N. H. 1845, p. 9. C. 

 (Ischno.) papillosus SHUTTLW. Bern. Mittheil. 1853, p. 77. Isch. 

 papillosus DALL, Catal. Mar. Moll. S.-E. U. S., in Bull. 37, U. S. 

 Nat. Mus., p. 172. 



This is the smallest of our Florida or West Indian Ischnoids. It 

 has much the same sculpture as the small Leptochitons, being uni- 

 formly granulated and having the lateral areas very indistinctly 

 defined. It is readily known from other Lschnochitons by these 

 characters. The original description is as follows : 



Shell small, wide ; greenish, closely maculated with whitish and 

 black; papillose; areas separated by a slender riblet; girdle very 

 finely scaly, alternately greenish and white. 



Length 5'25, breadth 3'25 mill. 



I. PUNCTULATISSIMUS Sowerby. PI. 21, figs. 35-38. 



Shell oval, moderately elevated, the dorsal ridge bluntly angular, 

 side slopes nearly straight. Surface apparently smooth, but seen 

 under a lens to be minutely and evenly granulated all over. Lat- 

 eral areas ill-defined. Flesh colored, speckled or dotted all over 

 with light brown, and often maculated on some of the valves or 

 along the dorsal ridge with dark brown. 



Lateral areas demarcated by a very low and obtuse ridge, obsoletely 

 sculptured by the intersection of two series of obliquely radiating 

 curved impressed lines; central areas similarly sculptured by 

 obliquely longitudinal lines. Urnbo of posterior valve in front of 

 the middle, the posterior slope concave. Interior blue-white, having 

 9-12 slits in the end valves, 1 in the median valves; teeth acute; 

 eaves moderate ; sinus wide, flat. Girdle covered with solid, flat- 

 tened, striated imbricating scales. Length 17, breadth 10 mill. 



Bays of Callao, Mexillones, Iquiqui and Arica, Peru, and Chili, 

 on dead shells, 6-10 fms. 



