296 AMER^JAN JOURNAL 



testae sequante ; apertura obliquata, semilunaris, subefifusa ; colu- 

 mella callosa. 



Bimensmis. — Long. 9, diam. 4 mill. 



Locality. — Pauraotus. 



Shell subulate, solid, wliite, longitudinally, finely, closely and 

 regularly striate ; whorls 6 — 7, convex, somewhat depressed at 

 the suture and marginated ; last whorl large, one half the length 

 of the shell ; aperture oblique, of a semilunar shape, slightly 

 efluse ; columella callous. 



RissoiNA STEiATULA, Pcase. Plate 24, fig. 31. 



Description. — T. crassa, subulata, alba, transversim tenui et 

 creberrime striata; anfr. convexis, ad suturam vix depressis, 

 anfr. ultimo magno ; apertura obliquata, oblongo-ovata; colu- 

 mella vix arcuata, callosa ; ad basim subeffusa. 



Dimensions. — Long. 9, diam. 3J mill. 



Locality. — Paumotus. 



Shell solid, subulate, white, transversely finely and closely 

 striate ; Avhorls convex, slightly depressed at the suture, last 

 whorl large ; aperture oblique, oblong-ovate, slightly effuse at 

 base of columella ; columella slightly arched and callous. 



The two last above-described species, with R ambigua, Gld., 

 form a group resembling each other in shape and form of aper- 

 ture, which is oblique, large and open. 



Amhigua is the smallest, distinctly ribbed, tenuistriata is 

 finely striate longitudinally, and striatula striate transversely. 

 All the species of this genus, heretofore described by me, from 

 the Hawaiian Islands, also inhabit the Islands of Southern 

 Polynesia. 



EissoA SEMicosTATA, Pease. Plate 24, fig. 32. 



Description. — T. oblongo-ovalis, subcylindracea, solidiuscula, 

 albida, aut pallide flavescens, transversim tenuistriata, longitudi- 

 naliter creberrime tenui costata, costis ad anfr. ultimum evanes- 

 centibus ; anfr. 5 — 6, convexo rotundatis ; sutura valde impressa ; 

 apertura parva, ovalis. 



Dimensions. — Long. 3, diam. 1\ mill. 



Locality. — Insl. Carolinfe. 



Shell oblong-oval, somewhat cylindrical, rather solid, whitish 

 or pale yellow, transversely finely striate, longitudinally finely 

 and closely ribbed, ribs obsolete or disappearing on back of last 



