RISSOIID^E. 321 



R. MIRABILIS, Dunker ; R. PLAXAXOIDES, Desm. Miocene of Aqui- 

 taine. 



The group was proposed first for fossil species, but the above re- 

 cent shell, referred by Semper to a new group Isselia (preoccupied, 

 and by Nevill to Isseliella, 1885, may be included. 



Subgenus EATONIELLA, Dall. 1876. 



Smooth, aperture subcircular, peristome simple, continuous, not 

 effuse below, lip margin- not thickened. Operculum paucispiral, 

 with an interior claviform process. R. KERGUELENEUSIS, Smith. 

 3 sp. Kerguelen Is. 



Name substituted for Eatonia, E. A. Smith, preoccupied. 



Genus BARLEEIA, Clark. 1855. 



Conically turbinated, whorls slightly convex, smooth ; aperture 

 oval, entire, rounded in front, lip sharp. Operculum subconcentric, 

 not spiral, with lateral nucleus, and an internal rib-like processs. 



Operculigerous lobe without processes, tentacles moderate, simple, 

 obtuse at their extremity, foot a little emarginate behind, truncate 

 in front. B. RUBRA, Adams. Europe. 



Many conchologists place this group in connection with Jeffrey- 

 siidse, rather than with Rissoiidse. 



Genus KEILOSTOMA, Desh. 1848. 



Elongated, turriculate, usually spirally striate ; aperture short, 

 entire, twisted at the base, angular behind, lip very thick, exteriorly 

 varicose, laterally produced, sinuous behind. 



Cretaceous and Eocene; Europe, India. K. EXIMIA, Desh. 

 (Struct. & Syst. Conch., t. 72, f. 39.) 



On account of Chilostoma, Fitz., 1833, Bayan, in 1873, changed 

 the above name to Paryphostoma. 



Genus FAIRBANKIA, Blanford. 1868. 



Shell imperforate, turreted, with a brown epidermis ; aperture 

 suboval, rounded in front, lip slightly dilated, with acute margin 

 and exterior varix. Operculum corneous, subannular, with an in- 

 terior long transverse rib. 



Animal with long filiform tentacles, and eyes sessile at their 

 bases ; proboscis elongated ; foot wide, sinuated in front, rounded 

 behind. F. BOMBAYANA, Blanf. Estuary; Bombay Harbor. 



21 



