CHITON. 155 



berculatus as seveh-valved ; and oddly enough, one of the specimens 

 collected by Dr. B. Sharp at Tobago is also apparently seven-valved, 

 having two of the valves firmly soldered together the result of an 

 early injury. It is likely that the seven and six-valved Chitons 

 described by early authors were partly abnormal specimens of this 

 character, and the rest were founded upon careless and incorrect 

 figures. 



Color-var. Color a uniform dull blackish ; riblets of the central 

 areas finer and converging near to the median line. Area behind 

 the sinus inside, and the slit-rays solid, not spongy or porous. 



Bermuda. 



I have seen a great number of specimens, but mostly so eroded 

 that the permanence of the characters could not be decided. 



Var. ASSIMILIS Reeve. PI. 33, figs. 61, 62. 



Fawn colored, with white dots on the lateral areas, the carina 

 banded with brown ; girdle light green. Central areas sculptured 

 with very fine, close riblets. Interior having the slit-rays and the 

 area behind the sinus porous. 



St. Thomas to Barbados. 



Chiton assimilis REEVE, Conch. Icon., t. 14, f. 76 (right hand 

 figure) ; f. 77b. (March, 1847.) 



Color-var. ater. (pi. 33, fig. 63). Shell having the close fine 

 sculpture of assimilis, but black in color, dark green-blue inside. 



St. Kitts (Rush) ; Trinidad (Sharp.) 



C. SQUAMOSTJS Liune. PI. 35, figs. 80, 81, 82. 



Shell oblong, elevated or rather depressed, carinated, the side- 

 slopes somewhat convex. Surface of lateral areas minutely beaded* 

 central areas smooth ; lusterless. Color buff (pale or deep in tint)' 

 the central areas regularly and conspicuously striped longitudinally 

 with gray or black, most valves having a wider dark blotch on each 

 side of the keel, and a series of spots along the back edge. 



The lateral areas and end valves are raised and sculptured ivith 

 radiating rows of fine beads, the number of rows increasing by inter- 

 polation ; and under a lens the surface is seen to be minutely punctate. 

 Central areas not sculptured, save for inconspicuous growth-lines. 

 Mucro of posterior valve near the front margin. 



Interior dark blue-green, the sutural plates lighter. Sinus rudely 

 denticulate. Anterior valve having 12, central valves 1, posterior 



