OF CONCHOLOGY. 



79 



tachment of the branchial plume to the body and the plumules 

 being tuberculated at their base, for reason probably of the large 

 size of the gill. After close examination of several specimens 

 no shell was found. 



Pleurobranchus ovalis, Pease. — Plate 9, fig. 3. 



Description. — Animal oblong-oval, smooth, subpellucid, convex- 

 ly rounded above, thin at the margins, rounded behind, slightly 

 concave in front. Foot oblong, nearly as wide as the mantle, 

 and projecting far posterior to the body. Tentacles well de- 

 veloped, smooth, scarcely tapering, cylindrical, truncate and in- 

 volute. Eyes black and immersed just behind the tentacles. 

 Oral veil large, notched in front, and extended laterally in 

 tentacular shape. Branchial plume free, on the posterior half 

 of right side, plumules tripinnate. 



Cream color, irregularly spotted, both as to shape and size, 

 with purple-red. A few similar spots on the head, veil and gill. 

 Mantle and foot narrowly edged, and extremities of the tentacles 

 tinted with the same color. 



Hob. — Tahiti. 



Dimensions. — Length two inches. 



Remarks. — Station under stones, in upper region of laminari- 

 an zone. 



The shell is very fragile. We have but an imperfect speci- 

 men, which is of the usual shape and size. 



Pleurobranchus delicatus, Pease. — Plate 9, fig 1. 



Description. — T. parva, solidiuscula, subpyriformi, postice con- 

 tracta, antice rotundata, vix flexuosa, striis incrementis induta, 

 rugulosa ; nuclei spirali ; antice violacea tincta, postice albida 

 aut pallide cornea. 



Shell small, rather solid, subpyriform, elongate, narrow pos- 

 teriorly, rounded in front, slightly flexuous ; surface rough and 

 marked with prominent lines of growth ; nucleus spiral ; anterior 

 portion stained with violet, posteriorly white or light horn color. 



Animal delicate, subpellucid, mantle smooth, oblong oval, 

 rounded at both extremities, convex along the dorsal region. 

 Foot elongate oval, rounded at both ends, entirely concealed by 

 the mantle. Tentacles slightly tapering to truncate tips. Oral 

 veil somewhat concave in front, produced laterally in tentacular 

 form. Branchial plume small, short. 



Color uniform orange-yellow throughout, the viscera impart- 

 ing a dark shade to the dorsal region. 



Hab. — Huaheine. 



