PIERCED SHELLS AND CHITONS 



255 



representative of this great group of 

 mollusks. The valves are smooth, 

 moderately arched in the center, and 

 are chiefly of a light reddish color. 

 This background of color is crossed 

 by wavy or zigzag lines of dark 

 brown, bordered above with white, 

 making the fresh specimen an object Fig. 252 

 of great beauty. The mantle border 

 is smooth, thin and delicate, and it is of a yellowish- 

 brown color. The length is about one inch. 



'^onicella marmorata^ Fabr., the Marbled Chiton, 

 has an oblong shell with valves elevated and rather 

 acutely angled. Its color is buif, closely sprinkled 

 with dark red; surface apparently smooth, but 

 microscopically granulated; length, 27 to 40 mm. 

 This species lives in the Atlantic and also in the 

 north Pacific. 



lionicella suhmarmorea^ Midd., the Red-spotted 

 Chiton. Valves rather depressed, apparently smooth 

 but microscopically full of granules; color, rosy or 

 yellowish-white, painted with spots and flamules of 

 red; length, 38 mm. From Fuca Strait past the 

 Aleutian Islands to Japan. 



T^rachydermon hartzvegii^ Cpr., Hartweg's Chi- 

 ton, has a low, oval shell, very closely and micro- 

 scopically granulated, and sometimes bears wart-like 

 granules irregularly scattered over the surface. Ex- 

 ternally it is of a dull olive-green, while internally 

 the color is an intense blue-green ; the length is about 

 an inch. It is found along the whole coast, from 

 Vancouver Island southward. 



