98 AMERICAN MARINE CONCHOLOGY. 



the lateral margins, which are rounded with an elevated marginal 



line. Medial areas lozenge-shaped, with numei'ous 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 1.5 to 15 mill. 



Whole Coast. 



3. C. ciNEREUs, Linnaeus. Fig. 200. 



Syst. Nat., edit. xii. 1107. 17G7. 

 Chiton marginatus, 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 T mill. 



New England. {Eur.) 



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



Fauna Groenlandica, 420. 1780. 

 C. fuhninaivs, Couthony, 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 aseUoides, Lowe, Zool. Journ., ii. 103, t. 5, f. 3. 

 Chiton sagrinatiis, 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.} 



