76 AMERICAN JOURNAL 



tracta, subangulata ; spira involuta, occulta ; labro vix arcuato, 

 margine acuto. 



Hab. — Huaheine. 



Animal elongate ; tail, margins of the foot and centre of nata- 

 tory lobes papillose ; tail long, arched, gradually tapering to a 

 rounded point. Tentacles four, auriform, subconvolute, some- 

 what dilated at the ends and truncate. Eyes immersed behind 

 the posterior pair. Natatory appendages thin, elongate, anterior 

 pair rather less than the whole length of the animal, posterior 

 pair a little shorter than the anterior, widest at their outer 

 halves and their sides, deeply incised, giving them a leaf-like ap- 

 pearance. Locomotive disk, like Aplysia. 



Color pale pea-green, tips of the tentacles tinged with yellow, 

 a dusky marginal band along the edge of the body ; the upper 

 surface of the natatory lobes are greenish centrally, fading into 

 yellowish pink towards the margins, which are white ; lower sur- 

 face of same color, but brighter, and margins dusky. 



Station among sea weed on sandy bottoms, in sheltered places. 

 When disturbed they cast off all their lobes, which retain their 

 vitality for several hours. 



Dolabrifera FUSCA, Pease. — Plate 8, fig. 4. 



Description. — T. elongato-triangularis, vix inflexa, basi rotun- 

 dato-truncata, striis decussata ; medio longitudinaliter sulcata ; 

 apice callosa. 



Shell elongate, triangular, right side straight, left side slightly 

 curved towards the apex, surface decussated with strife, lower half 

 grooved longitudinally in the middle ; base roundly truncate ; 

 apex callous ; whole shell slightly bent. 



Remarks. — The shells of all the species I have seen, inhabit- 

 ing Polynesia, are callous at the apex to secure the ligament 

 which holds the shell. They also differ from those heretofore 

 described, in being of a more triangular shape. The one here- 

 with figured may be taken as the type of them all. 



Animal oblong pyriform, widest posteriorly, and gradually 

 tapering in front. Surface smooth. Margins thin and ruffled, 

 rounded behind. Eyes immersed, a little anterior of the dorsal 

 tentacles. Tentacles openly convolute, dilated at their extremi- 

 ties and crenate. Color above uniform brown, right lobe, which 

 covers the gills, margined with white ; beneath pale bluish cen- 

 trally, passing into pale brown, and closely freckled with darker 

 brown and white. 



Station under stones, in the upper region of the laminarian 

 zone. The peculiarity of this species is the character of its mar- 

 gin, adapted for swimming. 



