GASTEROPODA. 339 
PaTteLLA Paumorensts (Gould ). 
Testa solida, albido-cinerea, ovalis, depresso-conica, apice sub-centrali, 
costis acutis radiantibus inequalibus ad quaterdents instructa: facies 
interna alba vel diluté incarnata ; impressione musculari callosa, alba 
vel citrind; area centrali ferruginea vel incarnescente : margo costis 
dentatus, spatits intercostalibus fusco tinctis. 
Patella Paumotensis, Goutp; Proceed. Boston Soc. Nat. Hist., ii. 
150. July 1846. Expedition Shells, 8. 
ANIMAL with the locomotive disk oval, gamboge-yellow ; head, ten- 
tacles, and mantle pale yellow; cirrhi of the mantle opaque-white ; 
mouth reddish. ‘Tentacles of moderate length and slender; eyes near 
the base; branchie interrupted at the head, arranged in a series of long, 
narrow, transversely striate lamelle; marginal cirrhi peculiar in ar- 
rangement, disposed in twenty-four clusters of five each, viz., two 
short ones, arising from the margin like a filamentary extension of the 
mantle, two rather longer ones from midway on the inside of the mantle, 
and between these a fifth, twice the size of the others, which is tubular, 
as are probably the others. [J. p. c. ] 
SHELL rounded-elliptical, depressed conical, solid. Colour ashy- 
white ; apex acute, one-ninth nearest the anterior end; surface with 
about forty unequal, acute, somewhat nodular ribs; muscular cicatrix 
unusually prominent, white or flesh-coloured, the included space 
rusty, especially near its margin, or occasionally tinted with rose- 
colour; marginal portion white or light flesh-coloured ; margin some- 
what regularly dentated by the prolonged ribs, the spaces between the 
ribs often more or less dusky. 
A specimen from Rose Island measures in length an inch and two- 
thirds; breadth an inch and a half; height half an inch. One from 
Wilson’s Island measures in length an inch and three-fifths ; breadth 
an inch and a quarter: height three-fifths of an inch. 
Allied to P. tramoserica, but its colours are generally dull and dead, 
instead of silky. Generally, eight or ten of the ribs are more promi- 
