TETHYS-POLYNESIAN. 93 



Shell somewhat talon-shaped ; oblique, arched, brownish-green, 

 subpellucid ; apex very elevated, acuminated, subauriculated ; upper 

 margin much sloped, excavated, outer lip rounded ; lower margin 

 rounded ; dorsal margin convex, subangulated. (Sowb.*). 



Sandwich Is. (Pease). 



Syphonota grandis PSE., P. Z. S., 1860, p. 23. Aplysia grandis 

 SOWB., Conch. Icon., pi. 8, f. 34a, b. 



This species was found gregarious on a rocky bottom. They 

 generally carry the mantle lobes expanded, spreading open and ex- 

 posing the shell and branchiae. When confined in a glass jar, they 

 used the posterior portion of the foot as a sucker, suspending them- 

 selves from the glass, although there was no division of the foot, as 

 in the preceding species. (Pse.). 



T. ELONGATA Pease. PI. 59, figs. 35, 36, 37, 38. 



Length (of alcoholic specimens) about 2 cm. Form oblong, 

 smooth. Back elevated, so much so as to give it a slightly com- 

 pressed appearance. Mantle lobes strongly dilated and undulated, 

 and free nearly the whole length of the back. Dorsal tentacles 

 rather slender, and ear-shaped; anterior pair large and dilated. 

 Foot narrow and terminating in a point posteriorly, which projects 

 beyond the back. Color of a darker or lighter brown, which color 

 is most intense on the top of the head and neck, The whole dorsal 

 region is clouded and minutely speckled with white. The shell is 

 distinctly defined in the living animal being covered with a thin 

 translucent membrane. (Pse.}. 



Swimming lobes narrow, membranous, united for a short distance 

 behind. Mantle having an extremely large oval foramen; excised 

 and lobed behind. Genital pore and groove as usual. 



Shell extremely large for size of the animal, moderately solid, buff 

 outside ; calcareous layer nearly as extensive as the cuticular. Very 

 convex, the apex incurved, bearing a wide, reflexed and adnate callous 

 hood. Sinus very deeply concave and short. Length 11}, breadth 8 



mill. 



Sandwich Islands (Pse. ; Townsend). 



Siphonota elongata PSE., P. Z. S., 1860, p. 24. MART. & LANGK. 

 Donum Bismarckianum, p. 54, pi. 3, f. 6. 



This seems to be a species allied to T. punctata and parvula, hav- 

 ing the shell of the same convex form, although provided with a 



