THE NAUTILUS. 51 
Several valves of a different Tonicia with rugose lateral areas and 
head valve, lirate pleural tracts, and sparse, excessively minute eyes 
also occurred. 
Ischnochiton comptus Gld. 
Ischnochiton Mitsukurii n. sp. 
Shell small, elevated, carinated, the side slopes slightly convex ; 
whitish, profusely speckled and clouded with brown, which color 
predominates toward the periphery. 
Valves not beaked, the sutural margins straight; lateral areas 
somewhat raised, sculptured with three or four very shallow, incon- 
spicuous, radial sulci, hardly visible on some valves; the diagonal 
line not conspicuous; entire surface cut into a fine, even granulation 
by the intersection of a series of forwardly converging with some- 
what stronger forwardly diverging grooves. Anterior valve evenly 
granular; posterior valve evenly granular, with central, scarcely 
projecting mucro, the slope behind it straight. 
Interior with the valve callus delicate purple; in front of it and 
at the insertion plates green. Sutural amine small, widely separ- 
ated by a wide sinus. Slits in valve i, ; in valves ii to vii, 1-1; 
in valve viii, 11. Teeth short, smooth; eaves narrow and solid. 
Girdle compactly covered with small, rather coarsely striated 
scales, measuring 0:14 mm. in average width. 
Length about 8 mm. Angle of divergence 90°. 
Japan. Exact locality not known. The name is in honor of the 
well known Japanese zoologist. 
Socorro Isianp, off Cape St. Lucas. 
A few species were collected by Mr. R. C. McGregor some time 
ago, and kindly presented to the Academy. 
Chiton articulatus Sowb. Very large specimens, measuring 90 
mm. long. 
Chetopleura sp. undet. A species allied to Ch. columbiensis but 
with very few pustules on the lateral areas. The surface having 
suffered from immersion in strong formalin, it is hardly in condition 
for description. 
Trachydermon dentiens (Gld.). 
Rather small, black with indistinct dirty yellowish speckling and 
the usual sutural dots. Gills ambient, 15 on the right, 13 on the 
left side. Socorro Island lies over 500 miles south of the souther- 
most previous locality for this species. 
