170 CHITON. 



Inside: anterior valve having 8; central valves 1, posterior 

 valve 18 slits; teeth normal, very closely pectinated ; sinus narrow, 

 having about 12 minute denticles. 



Girdle unicolored or tessellated, bearing normal imbricating scales 

 which here and there are very minutely striatulate. 



Length 58, width 33 mill.; divergence 110. 



Japan (Mus. Cum., no. 16.) 



This species, says Carpenter, from whose MS. the above descrip- 

 tion is taken, is easily recognized by the very close ribs, arranged like 

 miniature whale bone. 



C. MARQUESANUS Pilsbry, n. sp. PL 36, figs. 98, 99, 100. 



Shell oval-oblong, depressed, obtusely carinated, the side-slopes 

 nearly straight. Surface smooth and polished on the central, granose 

 and lusterless on the lateral areas. Color dark olive-green, almost 

 black on the lateral areas and end valves. 



Lateral areas but slightly raised, sculptured with about seven 

 uneven and unequal rows of separated low warts, and under a lens 

 seen to be covered with a minute granulation ; central areas shining, 

 having a few low growth-wrinkles and covered with a partly effaced 

 microscopic granulation. End valves closely granose in indistinctly 

 radiating pattern; mucro near the front margin of the tail valve. 



Interior light blue, stained at sinus and under the beaks with 

 purple-brown ; sinus rather shallow and toothed. Anterior valve 

 having 21, central valves 1, posterior valve 25 slits. 



Girdle dark green, covered with convex scales, which in the 

 middle of its breadth are larger and carinated. 



Length 46, breadth 26 mill. 



Marquesas Is. (Garrett.) 



The papillose lateral areas, smooth central areas and uniform dark 

 olive-green color are the more striking features of this species. The 

 large number of slits is also noteworthy. The specimen before me 

 was presented to the Academy by the late Andrew Garrett, and it 

 was labelled " C. marquesana;" but whether this name was given by 

 Garrett or by Tryon I do not know. 



C. PERVIRIDIS Carpenter. 



Shell small, narrow, elevated, the jugum acute ; color an intense 

 green. Entire surface very minutely scaly under a lens ; lateral 

 areas and end valves radially lirate, the line obtuse, little con- 

 spicuous, 4 or 5 on side-areas, 20-25 on end valves. Central areas 



