CHITON. 261 



Shell small, strong, nearly oval, being but slightly narrowed be- 

 fore, convexly elevated and traversed by an elevated ridge or keel 

 along the back ; valves without any appearance of granulations or 

 punctures under the magnifier, but marked with conspic- 

 uous grooves, indicating the stages of growth, most marked ^'^' ^^' 

 near the border ; otherwise perfectly smooth, shiiung, and 

 })olished ; posterior margin strongly beaked. Color, light 

 brick-red or flesh-color, with occasional dashes of dark 

 crimson across one or more valves, sometimes arranged ^ ^^^^ 

 in stripes ; such a stripe will usually be found at a little 

 distance on each side of the keel, while the keel itself has a stripe 

 of crimson spots, occasionally replaced by a yellow spot. It is fre- 

 quently incrusted with a black foreign substance. Margin coria- 

 ceous, coated with a red and white dust arranged in alternate 

 stripes. Triangular areas generally well marked. Interior bright 

 rose-red, becoming fainter at the margins of the valves. Length, 

 half an inch ; breadth, three tenths of an inch. 



Found adhering to stones dragged from the deep by kelp ; also in 

 the maws of fishes. Eastport ( Cooper) ; on stones, Halifax Harbor 

 ( Willis) ; Greenland (^Muller) ; Cape Cod, northward (^Stimpson) ; 

 Connecticut (^Linslei/). 



It is not difficult to disthiguish at sight well-marked individuals 

 of this species from those of C. fidmitiatus. But there are inter- 

 mediate specimens which it is not easy to pronounce upon. In gen- 

 eral, this species is smaller, more solid, more convex, the valves 

 more beaked, lines of growth more deep, the zigzag lines never 

 api)earing, though the posterior margin of the valve is sometimes 

 dotted with white and red. The impunctured or ungranulated sur- 

 face, however, is the best, as it is a constant characteristic. 



That this is the C. ruber of Lowe and Sowerby I think there can 

 be no question, though it may not be C. ruber of other authors. The 

 figure in Pennant, " Brit. Zool.," pi. 36, fig. 3, also represents ac- 

 curately most of the adult specimens, though it is quoted by authors 

 as C. IfBvis, which is distinguished by its finely reticulated margin. 



Chiton marmoreus. 



Shell ovato-oblong, brownish or yellowish red, variegated with angular, whit- 

 ish lines, and a series of whitish points along the posterior margin of the valves; 

 surface minutely granulated ; margin pubescent. 



Chiton mnrmomts, O. Fabrioids, &.C. ; Stimpson, Check Lists, 4. 

 Chiton IxBvigatus, Fleming, &c. 



