322 RISSOIID^E-JEFFREYSIIDjE. 



Combines the epidermis, and to a great extent the animal of Hy- 

 drobia, with the peristome of Rissoia and the operculum of Jeffrey- 

 sia. 



Genus IRA V ADI A, Blanford. 1867. 



Rissoiform, the apex often obtuse, whorls spirally ribbed and 

 covered with an epidermis; aperture ovate, margins continuous, 

 anteriorly slightly effuse, outer lip with an external varix. Oper- 

 culum and animal unknown. 



Brackish water. India. I. ORNATA^ Blanford. 



Probably closely related to Fairbankia. 



Genus FENELLA, A. Adams. 1871. 



Shell turriculate, subulate, or pupoid, whorls cancellated ; aper- 

 ture oval in front, peristome interrupted, lip sharp, thickened or 

 varicose. F. PUPOIDES, A. Ad. Japan. 



Some authors place Fenella in Pyramidellidse. 



Genus PUTILLA, A. Ad. 1867. 



Shell turbinated-conic, solid, smooth, rimate ; aperture suborbic- 

 ular, lip thickened, subeffuse in front, scarcely expanded. Relation- 

 ships obscure. P. LUCIDA, A. Adams. Japan. 



Genus SKKNELLA, Pfeffer, 1886. 



Shell depressed globose, compressed around the umbilicus; peris- 

 tome continuous, the inner lip straight, oblique ; operculum pauci- 

 spiral, with a projecting lamina, arising from the nucleus. 



S. GKOIKJIAXA, Pfeffer. 

 South Georgia. 

 FAMILY JKW/fK YSIIDJE. 



Proboscis bilobed in front, forming two sharp, narrow, ciliated 

 appendages as long as the tentacles, which arc' equally ciliated ; 

 eyes sessile at the base of the tentacles; toot lanceolate. Jsiws 

 scaly (PI. 54, fig. 2 i. Radulu variable, short, the central tooth 

 small, with slightly reflected margin, lateral tooth arcuate, some- 

 times denticulate, sometimes unarmed, marginal teeth absent or 

 present ( PI. 54, fig. 1 ). 



Shell smjill, thin, transparent, wit li oval aperture. Operculum 

 imbricated, concentric, with marginal nucleus, the inner face With 

 a transverse carina (PI. 54, figs. !HI, !)7 *. 



