NUTTALLINA. 283 



cation of from 50 to 100 diameters is necessary to demonstrate it in 

 many specimens. 



N. CINEREA Poli. PL 54, figs. 28-33. 



Shell oval, moderately elevated, not carinated, the side slopes 

 straight. Surface lusterless, generally encrusted with calcareous 

 growths, gray or greenish blotched with black or dark green with 

 some light markings or light valves. 



The median valves are beaked when young, but eroded and 

 hardly beaked when adult, the lateral areas not raised but marked 

 by two low wide rounded ribs with a shallow depression between them ; 

 one rib diagonal, the other at the posterior border. Entire surface 

 of all valves evenly covered with comparatively coarse granules. 

 Anterior valve having 8 or 9 low rounded radiating ribs. Posterior 

 valve very small, the mucro somewhat behind the center, the slope 

 behind it straight ; posterior margin emarginate (as in Eudoxochiton, 

 p. 193.) 



Interior bluish in the middle, olive-greenish at the sides. Sinus 

 rather deep and angular, very porous or spongy. A more or less 

 distinct laminate triangle extending from sinus to beak. Anterior 

 valve having 8 or 9 slits corresponding in position to the external 

 ribs ; the slits are very short, but are continued as grooves to the 

 eaves outside ; median valves with 1 slit ; the anterior teeth nearly 

 smooth, distinctly thickened or " propped " outside at the slits ; pos- 

 terior valve having slits, the teeth rather stumpy, short in the mid- 

 dle behind, longer and directed forward at the sides. Eaves rather 

 wide and coarsely spongy. 



Girdle narrow, alternately dark and light, compactly covered 

 with small, subcircular or irregularly polygonal scales, striated on 

 the convex outer surface, crowded together ; the margin beset with a 

 series of slightly flattened, striated translucent bristles, (figs. 31, 33). 



Length 14, breadth 8 mill. 



Length 20, breadth 12 mill. 



Entire Mediterranean and Adriatic Seas; Atlantic Ocean at 

 Cadiz, Spain. Littoral zone. 



Chiton cinereus (+ Lophyrus melphictensis) POLI, Test. utr. 

 Sicil. i, multivalvia p. 4, t. 3, f. 1-20, (1791). Not C. cinereus 

 Linn. C. caprearm SCACCHI, Cat. Conch. Regni Neapolitan!, p. 9 

 (1836) teste Monts. C. caprearum Scac., BUG., DAUTZ. and DOLL- 

 PUS, Moll. Mar. Rouss. i, p. 492, t. 61, f. 7-9 ; t. 62, f. 1 (1886). 



