LOBIGER. 169 



produced. Aperture seraioval, obliquely truncated in front, sub- 

 angulated behind; columellar lip thin, with a thin, narrow callus 

 recurved over the spire ; outer lip thin, arcuate and simple. 



Alt. 7, diam. 5 mill. Swimming lobes two, one anterior, the other 

 posterior. (Fischer.') 



Guadeloupe, West Indies. 



L. souverbii FISCH., Journ. de Conchy!., v, 1856, p. 273, pi. 11, f. 

 7-10. L. sowerbyi Fisch., MORCH, Malak. Bl., xxii, p. 179. 



Differs from the other forms known in the single pleuropodial 

 lobe on each side. 



Subgenus PTERYGOPHYSIS Fischer, 1883. 



Pterygoplnjsis FISCHER, Man. de Conch., p. 571. 



Four tentacles developed on head ; pleuropodial lobes four, very 

 long, with scalloped edges. 



L. VIRIDIS Pease. PI. 10, figs. 37, 38. 



Shell ovate, rather thin, longitudinally striated, white, covered 

 with a yellowish epidermis ; left margin slightly dilated. Aperture 

 oblong-oval, rounded in front, produced, contracted and subangulate 

 behind. Spire involute, concealed ; lip slightly arcuate, its margin 

 acute. (Pse.). 



Animal elongate ; tail, margins of the foot and centre of natatory 

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

 point. Tentacles four, auriform, subconyolute, somewhat 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 in- 

 cised, giving them a leaf-like appearance. Locomotive disk like 

 Aplysia. Color pale pea-green, tips of the tentacles tinged with yel- 

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

 surfaces of the natatory lobes are greenish centrally, fading into 

 yellowish pink towards the margins, which are white ; lower surface 

 of same color, but brighter, and margins dusky. 



Tahiti (Mts.); Huahine, among sea-weed on sandy bottoms in 

 sheltered places (Pse.). 



Lobiger . . . . f PEASE, P. Z. S., 1861, p. 246; Lobiger 

 viridis PEASE, P. Z. S., 1863, p. 510^ L^piota EgE., Amer. Jouru. 



