316 MOLLUSCA. 
Cuiron prutnosus (Gould). 
Testa parva, oblongo-elliptica, convexo-elevata, subcarinata, coloribus 
vartis olivaceis, cinerets, et fusco-rubris trrorata et maculata ; areis 
centralibus sub lente omnino quincuncialiter punctatis ; arets laterali- 
bus longitudinaliter imbricato-striatis : intus virescens: margo minu- 
tissimé granulatus, coloribus fuscis et cinereis tessellatus. 
Chiton pruinosus, GouLp ; Proceed. Boston Soc. Nat. Hist., 11. 144. 
July 1846. Expedition Shells, 5. 
ANIMAL “with the foot and head a warm flesh-colour beneath, the 
latter small, the buccal mass almost circular, only a little tubercle 
on each of the sides next the foot. Lateral portion of foot and head 
a dark brown; branchie interrupted behind, of a clear, transparent 
red. Inside of margin a greenish ochre.” [1. P. C.] 
SHELL small, elongated, nearly elliptical, convexly elevated, sub- 
carinate, or rather somewhat doubly carinate along the back ; surface 
generally covered with microscopic punctures, arranged in lozenge. 
Lateral areas very slightly raised, and longitudinally imbricate-sul- 
cate; central areas with faint lines of growth and punctures in quin- 
cunx; anterior valve concentrically striate, not punctate; posterior 
valve slightly umbonate, and crossed by a transverse ridge, behind 
which it is concentrically striate. It is frosted or mottled with dark 
brown, ash, purple, green, &c. Margin minutely granulated, so as 
to look hoary. 
Length seven-tenths of an inch; width seven-twentieths of an inch. 
Found on stones off Fort Santa Cruz, Rio Janeiro in two or three 
fathoms water. 
Mr. Couthouy remarks as to the coloration, “some specimens are of a 
uniform pale green, margin clouded with dark green; some had two or 
three distinct, white blotches on the sixth valve, the rest of the shell 
being olive-green, with a line of faint green along middle of back; an- 
other had the ground-colour a clear olive, three dark brown spots bor- 
dered with white on each side of posterior margin of valves, a row of 
similar spots surrounding the terminal valves just above insertion, and 
