CHITON. 263 



Chiton albus. 



Fig. 21. 



Shell small, elliptical, valves cariuated and partially beaked, minutely granu- 

 lated ; margin beaded. 



Chiton albus, Montagu, Test. Brit. 4. — Sowerby, Conch. Illust. 99, 99 «, 100. — 

 Brown, Conch, of Great Brit. &c. pi. 35, fijr. o. — Gould, Inv. 1st ed. 150, fig. 

 21._De Kay, N. Y. Moll. 1G3, pi. 10, fig. 200. — Sti.mpson, Check Lists, 4. 



Chiton aselloldes, Lowe, Zool. Jourii. ii. 103, t. 5, fig. 3. — Wood, Suppl. pi. 1, fig. 9. 



Chiton sagrinatus, Couthouy, Am, Journ. Sc, o. s. xxxiv. 217 (1838); Bost. Journ. 

 Nat. Hist. ii. 82. 



Shell small, elongated-oval ; covered with a bluish black pigment, 

 which easily rubs off, and leaves the ground yellowish or ash col- 

 ored ; surface beautifully granulated, under the microscope, 

 so as to resemble the finest shagreen. Valves moderately 

 cariuated, and with a minute beak ; distinctly marked with 

 lines of growth, and a feeble diagonal ridge often divides 

 each side into two triangles ; anterior valve crescentic, with ^. ,^ 



~ ' ' C. albus. 



about twelve marginal teeth. Margin membranous, yellow- 

 ish, covered with Ijeaded granules. Length, nine twentieths of an 

 inch ; breadth, five twentieths of an inch. 



Found in the stomachs of fishes in considerable numbers. Isle 

 of Shoals to Cape Cod (^Slimpson) ; Eastport {Cooper); Halifax 

 {Willis). 



This shell was first discovered on this side the Atlantic by Mr. 

 Joseph P. Couthouy, and supposed by him to be new. But it agrees 

 in all respects with Mr. Lowe's figure and description of C. asel- 

 loides ; and Mr. Sowerby, on an examination of our shell, accords 

 with me in opinion that it is that shell. Mr. Lowe subsequently 

 states (Zool. Journ. iii. 79) that his species " is clearly identified 

 with C. albus of Montagu." But, as it is only white when divested 

 of its pigment, the name aselloides is much more descriptive. 



The ridges, edges, and interstices of the valves usually have the 

 pigment worn off, so as to present a yellowish color. The beaded 

 margin distinguishes it from all our other species ; but it is rare to 

 find the margin unimpaired. 



Chiton mendicarius. 



Shell elongate in its centre towards its margin, granulated longitudinally and 

 irregularly ; clouded ; areas scarcely conspicuous ; margin coriaceous, red. 



Chiton mendicarius, Mighels and Adams, Bost. Journ. iv. 42, pi. 4, fig. 8 (1842) ; Proc. i. 

 49 (2841). — Stimpson, Check Lists, 4. 



