GENA. 41 



O. L^EVIS Pease. PL 55, figs. 15, 16 (enlarged). 



Shell oblong, flatly depressed on its upper side, rounded on its 

 lower edge, smooth, solid, marked transversely by striae of growth ; 

 outer lip straight, inner lip thickened on its edge ; aperture oblong 

 oval ; spire posterior, small, slightly elevated ; greenish-olive, va- 

 riously spotted or mottled with white, brown or red, sometimes wholly 

 of a dark green color. Length 11, diam. 6J mill. (Pse.) 



Tahiti. 



Gena Icevis PSE., Arner. Journ. Conch, iii, p. 283, t. 23, f. 7, 28, 

 29 (1867). 



This is a depressed form, polished save for close, fine spiral striae 

 on the penultimate and beginning of the body-whorl, which are 

 continued around the base as in other smooth Gena. The spire has 

 a faint keel sketched around the shoulder. The outer lip is some- 

 what sinuous. The shell is supported by the extremities when 

 standing upon a plane. 



Length 9J, breadth 5 mill.; convexity 2J mill.; aperture, length 

 8, breadth 4-9 mill. 



The animal lives in the upper region of the laminarian zone, 

 on branched coral, but is usually found under loose stones, on mud 

 or sandy bottom, at low water-mark. The color above is similar to 

 that of the shell, of an olivaceous or brownish-olive, reticulately 

 veined with dusky, lomocotive disc and tentacular appendages pale. 

 The first is large and cannot be wholly retracted beneath the shell ; 

 it is oblong rounded behind, thick and fleshy, ciliated around the 

 margin, and slightly tuberculated on the posterior upper portion. 

 When expanded, three hirsute cylindrical tapering cirri project from 

 each side of the shell, which are attached to the upper surface of the 

 foot, and at the outer base of each is a minute aborescent appendage. 

 The mantle is margined with a single series of pinnate cirri, which, 

 when the animal is in motion, are recumbent on the margin of the 

 shell. Head proboscidiform, well developed, lips wrinkled, mouth 

 elliptical. Tentacles very long, tapering and hirsute. Two abores- 

 cent appendages in front of the tentacles. Eyes on hirsute pedicels 

 at the hinder base of the tentacles. A siphon projects on each side 

 of the neck, the left incurrent, and the right excurrent ( Garrett in 

 Pease, loc. cit.). 



G. ROSACEA Pease. PL 55, fig. 12. 



Shell oblong oval, convex, somewhat depressed on upper side near 

 the apex, rather thin, concentrically distantly and elevately striate, 



