14 MOLLUSCA. 
Succinea putamen, GOULD; Proceed. Boston Soc. Nat. Hist., 11. 182. 
Nov. 1846. Expedition Shells, 28. 
Animat much larger than the shell, forming, when extended, a 
broad, oval disc, twice the length of the shell, the foot sometimes 
advancing in front of the head; mantle considerably surpassing the 
shell; respiratory orifice on the right side, a little behind the middle 
of the shell; flesh-coloured, dotted with brown, especially on the 
cheeks, between the tentacles, and on the top of the foot, and having 
faint diverging lines on the flanks. 
SHELL semi-ovoid, very thin and transparent, becoming thickened 
and opaque and pale when superannuated, of a brownish horn-colour 
when fresh ; surface smooth and regular. Whorls scarcely two, the 
upper one merely indicated by a sutural line, not prominent, but co- 
incident with the general surface. There are a few faint revolving 
strie, more especially posteriorly. Beneath plane, the aperture nearly 
as large as the shell, regularly oval, the lip somewhat decurrent on the 
left side ; the columella has a distinct fold far back, in large specimens, 
and considerable enamel. 
Length of axis five-eighths of an inch; breadth half an inch. 
Inhabits moist places, and especially taro-patches, at the island of 
Upolu. 
A remarkable shell, resembling the half of a bird’s egg. Distin- 
guished from S. rotundata by its larger size, revolving strie, and an- 
gular periphery. 
The animal is evidently quite distinct from the usual form of Suc- 
cinea, and would perhaps be ranked under Férussac’s genus Helico- 
limax. At any rate, this with the two following species, belong to a 
peculiar group; and I am not aware of any similar form being found 
elsewhere than at the Navigator’s and Sandwich Islands. 
Figure 16, animal with the shell, viewed laterally ; 16 a, the same 
seen from above ; 16 0, aperture of the shell. 
