98 AMERICAN MARINE CONCHOLOGY. 



the lateral margins, which are rounded with an elevated marginal 

 line. Medial areas lozenge-shaped, with numerous elevated 

 rounded dots arranged in ten or twelve series on each side of the 

 carina, parallel with the longitudinal axis of the body ; grayish, 

 bluish, or ferruginous. 



Length 13 to 25, width 7.5 to 15 mill. 



Whole Coast. 



3. C. CINEREUS, Linnseus. Fig. 200. 



Syst. Nat., edit. xii. 1107. 1767. 

 Chiton marginatm, Pennant, Brit. Zool., iv. 61, t. 36, f. 2. 1777. 



Shell small, ovate, carinate and pointed behind ; surface appa- 

 rently smooth, but under the lens minutely shagreened in dia- 

 mond-shaped granules ; dull ashen or greenish. 



Length 12, width 7 mill. 



New England. (Eur.) 



4. C. MARMOREUS, Fabricius. Fig. 201. 



Fauna Grceulandica, 420. 1780. 

 C. fulminatus, Couthouy, Bost. Journ. Nat. Hist., ii., p. 80, t. 3, f. 19. 1838. 



Shell oblong-ovate, rather flat, color varying from bright red to 

 yellowish or dark reddish-brown, with numerous fine zigzag whit- 

 ish lines arranged over the whole surface, and a line of six or 

 eight whitish spots alternating with dark red along the posterior 

 edge of each valve ; valves carinated and slightly beaked, their 

 surface covered with microscopic granulations arranged in quin- 

 cunx ; triangular areas very indistinct; margin narrow, coriaceous, 

 coated with a close, short down, alternately red and white. 



Length 17.5, width 11.3 mill. 



New England. (Eur.} 



.5. C. ALBUS, Montagu. Fig. 202. 



Test. Brit. 4. 1803. 



Chiton aselloides, Lowe, Zool. Journ., ii. 103, t. 5, f. 3. 

 Chiton sagrinatus, Couthouy, Am. Journ. Sci., xxxiv. 217. 1838. 



Shell small ; valves with a small beak, minutely crenulate on their 

 anterior margin, subcarinate, with minute striae ; surface minutely 

 shagreened ; an obsolete diagonal ridge sometimes divides each 

 side into triangular areas, but for the most part without any 

 distinct boundary; margin membranous covered with beaded 

 granules ; grayish-white under a pulverulent black epidermis ; 

 marginal membrane ashy, with a narrow black median band. 



Length 10, width 3.7 mill. 



New England. (Eur.) 



