MALACOZOA. GASTEROPODA. CYCLOBRANCHiATA. 185 



4. Chiton fuscdtus. Dusky-grey Chiton. 



Shell oblongo-elliptical, a little narrower anteriorly, carinate, 

 with the sides sloping and marked with a faint longitudinal 

 depression ; the valves eight, minutely granulate ; the an- 

 terior semicircular, marginate, with dots in quincuncial striae ; 

 the posterior similar, with its anterior half carinate ; the rest 

 narrow, marginate, carinate, somewhat heaked, with an ob- 

 lique, obtuse ridge on each side, somewhat more elevated in 

 the middle, from the beak to the extremity of the anterior 

 margin, the anterior area with rather irregular longitudinal 

 series of granules, the two posterior with irregularly-disposed, 

 somewhat quincuncial granules ; the border granulate, with 

 the margin membranous ; the colour uniform dull leaden-grey, 

 that of the interior bluish. Length seven-twelfths, breadth 

 four-twelfths. 



Found by Mr. Alexander Murray, in September, 1842, in 

 Cruden Bay. 



This species is quite distinct from Chiton cinereus, of which 

 the markings are finer and more regularly disposed. 



Chiton fuscatus. Brown, Illustr. PI. 35. f. 17. 



5. Chiton Icemgdtus. Smooth Canoe-Shell.^ 



Shell broadly elliptical, a little narrower anteriorly, sub- 

 carinate, with the sides sloping and slightly convex; the 

 valves eight, minutely granulato-striate ; the anterior lunato- 

 semicircular, with minute radiating granulated striae ; the pos- 

 terior semicircular, with growth-lines, and radiated in the 

 same manner; the rest narrow, marginate, obtusely subcarinate, 

 not beaked, with the posterior areas very slightly raised and 

 radiatingly striulate, the anterior with longitudinal striulae, 

 the prominent medial part nearly smooth ; the border granu- 

 late, narrow ; the colour dull reddish-white with longitudinal 

 streaks of reddish-brown, radiating on the anterior and pos- 

 terior valves ; the interior flesh-coloured. Length three- 

 twelfths of an inch, breadth two-twelfths. 



Found by Miss Isabella Macgillivray on a shell from deep 

 water off Aberdeen, on the 30th September, 1842. 



Chiton laevigatus. Flem. Brit. Anim. 290. 



Q 2 



