SETIA. 333 



Genus CERATIA, H. and A. Adams. 



Tentacles flat, rather short, claviform at the tip, clothed 

 with aciculate setae ; foot divided behind into two long, 

 distinct tails; operculigerous lobe without a caudal 

 cirrhus. 



Shell sub-cylindrical, spirally striated, white, semipel- 

 lucid, thin, whorls rounded, the last nearly as long as 

 the spire, suture deep, apex of spire obtuse; aperture sub- 

 ovate, peristome continuous, outer lip thiu, acute, simple. 



Ex. C. proxima, Alder, pi. 35, fig. 6. 



This genus, founded on the Rissoa proxima of Alder, is 

 remarkable for the bifid nature of the hind part of the 

 foot, resembling, in this respect, the tail of Nassa. 



Genus SETIA, H. and A. Adams. 



Tentacles pilose ; foot simple behind ; operculigerous 

 lobe small, without a caudal cirrhus. 



Shell thin, obovate, oblong, or subconic, sub-umbili- 

 cated, whorls few, ventricose, spotted ; spire short, apex 

 obtuse ; aperture suborbicular, narrowed behind ; inner 

 lip somewhat straight ; outer lip thin, simple, acute. 



Ex. S. pulcherrima, Jeffreys, pi. 35, fig. 7. 



In this small group, founded on the Rissoa pulcherrima 

 of Jeffreys, the opercular lobe is simple, the tentacles are 

 pilose, and the shells are umbilicated, with spot-like mark- 

 ings on the whorls. 



