NO. 2223. CHITONS FROM THE NORTHWEST PACIFIC— BERRY. 7 



pustules projecting as dentations past the valve margin; central 

 areas ornamented by some 22 (valve 7) to 26 (valve 4) nodulose 

 ribs, for the most part slightly curved toward the jugum, connected 

 by a series of much fainter and more irregular crossbars, the entire 

 complex becoming reduced to a scarcely regular reticulum over the 

 jugal tract. Posterior valve with central and posterior areas clearly 

 marked, their sculpture closely similar to that of the intermediate 

 valves; posterior area with some 18-24 pustulose radiating ribs, from 

 which the pustules seem very often to be rubbed away (pi. 4, fig. 7). 



Girdle wide, averaging about one-fourth the width of the median 

 valves. Dorsal scales translucent, scarcely imbricating, strongly 

 convex, the convexity directed obliquely outward and forward (ex- 

 cept in the posterior region), and arranged with a fair degree of 

 definiteness in oblique lines; variable in size, the largest occurring a 

 short distance from the shell, the smallest at the margin; all dis- 

 tinctly ribbed-striate on the upper convexity, the number of striae 

 being generally about 7 to 10 on the larger scales (pi. 4, figs. 5-6). 

 Marginal scales minute, transparent, delicate, spiniform, finely 

 striate, but a few smooth, needle-like spines now and then appearing 

 among them. Ventral scales similar to the marginal, but elongate 

 rectangular, and ranked in closely placed transverse series (pi. 3, 

 fig. 6). 



Color of shell in alcohol a warm orange brown, heavily mottled, 

 and variegated with both darker and lighter tints. Girdle with 

 alternate bands of orange brown and tan. Ventral surface a light 

 pinkish tan. Interior of shell grayish pink with lavender clouding. 



The radula has strong bidentate major laterals (pi. 3, fig. 7), but 

 its further details have not yet been successfully worked out. 



Ctenidia about 28 on each side, extending to a point nearly opposite 

 the middle of the third valve. 



Length of entire animal (type-specimen) 21, of shell 19 mm.; 

 width of same 12.25, of shell 7.5 mm.; maximum width of girdle, 

 2.5 mm. 



Type.— Cat. No. 215630, U.S.N.M. [S. S. B. 112]. 



Type-locality. — Station 4808,^ 47 fathoms; bottom of sand, shells, 

 and coarse gravel; off Cape Tsiuka, Japan; July 16, 1906 (three 

 specimens). 



Remarks. — This very attractive species seems chiefly character- 

 ized by the ruddy tones of its prettily maculated color scheme, the 

 very weakly dentate sinus, the bidentate major laterals of the radula, 

 and the small, httle crowded, strongly ribbed girdle scales. The 

 sculpturing of, the central areas considerably resembles that of the 

 following species, but here the longitudinal riblets are narrower, 

 rougher, and have interspaces distinctly wider than the ribs, differ- 

 ences which are not shown well in the figures. A brief comparison 



1 The station number appearing on the original specimen label is 4708, but this seems clearly erroneous. 



