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 8'<, breadth 5 mill. 



Length 5-}, breadth 35 mill. 



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

 (Hemphill). 



Chiton papillosm AD., Proc. Bost. Soc. N. H. 1845, p. 9. 0. 

 (/sc/wo.) papillosm SHUTTLW. Bern. Mittheil. 1853, p. 77. Isch. 

 j>/>illonu8 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 Ischnochitons 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. Umbo 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, Mexilloiies, Iquiqui and Arica, Peru, and Chili, 

 on dead shells, 6-10 fms. 



