JEFFKEYSIIDiE-SKENEID^. 323 



Genus JEFFREYSIA, Alder. 1849. 



Characters those of the family. Distr. Europe, Japan. 



J. DiAPHANA, Alder. 

 Jeffreysia lives ou algse, from which it can suspend itself by a 

 - mucous thread. The eyes are visible through the shell. 

 Bissoella, Gray, 1847 (not described), is a synonym. 



Subgenus Tatea, Tenison Woods. 1879. 



8hell elongate })yramidal. Operculum calcareous, with a vertical, 

 *ubmarginal claw. Animal with truncate foot and long tentacles. 

 T. Huonemsis, Woods. Tasmania. 



Subgenus Dardania, Hutton. 1882. 



Shell ovate, subconical, smooth, imperforate, olivaceous ; aperture 

 oval, entire, roiinded in front ; peritreme not continuous, outer li]> 

 thin. Operculum like Jeft'reysia. D. olivacea, Hutton. 



New Zealand. 



Family SKENEID.E. 



Head large, proboscidiform, foot truncate in front, operculigerous 

 lobe without appendages, tentacles long, cylindrical, eyes nearly 

 sessile, at their external base (PI. 54, fig. 100). Jaws tuberculate. 

 Badula like Hydrobia (PL 54, fig. 99). 



Shell depressed, nearly discoidal, few-whorled, widely umbili- 

 cated, aperture rounded, peristome continuous. Operculum corne- 

 ous, multispiral. 



Genus SKENEA, Fleming. 1828. 



Characters those of the family. Northern Seas. Low water, 

 under stones and on alg?e. S. planorbis, Fabr. 

 Delphinoidea, Brown, is a synonym. 



Family CHORISTIDjE. 



Shell heliciform, thin, perforate, covered by an epidermis ; aper- 

 ture oval, ])eristome continuous, sharp. Operculum corneous, 

 spiral. 



Head short, large, two short anterior tentacles are connected by 

 a frontal veil, the posterior tentacles are simple, tiiick, conical ; no 

 eyes ; proboscis retractile ; foot large, oval, with two anterior ten- 



