GASTEKOPODA. 



Shell turreted, umbilicated or rimose ; aperture more or less 

 circular ; peristome continuous ; margin straight, acute. 



The species haye the habit of agglutinating grains of sand to 

 the surface of the shell. 



Distribution, 4 species. Japan, Philippines, 2 — 70 fathoms. 



Fossil, 1 species. Oligocene, Latdorf. 



MiCEOSTELMA, A. Adams, 1863. 



Type, M. Dsedala, Adams. Japan, 48 fathoms. 



Shell turreted, ovate, rimose, somewhat resembling Pyrami- 

 della ; spire conical ; whorls longitudinally plicated. Aperture 

 oblong, produced in front, sub-canaliculate; columella thick- 

 ened, straightish ; lip simple. 



Fossil, 1 species. Sub-apennine formation. Asti, Italy. 



Baeleeia, Clark. 



Named in honour of the late G. Barlee. 



Type, Turbo ruber, Montagu. Britain, Mediterranean. 



Animal and shell related to Rissoa ; nmntle and opercular lobe 

 destitute of filaments ; operculum solid, auriform, and gibbous, 

 nucleus excentric. 



Distrihution, 3 species. Atlantic and Pacific Oceans. 



[Family SsEisrErDiE] 

 Includes Shenea (p. 256), and 



HoMAXOGTBA, JeflFreys, 186Y. 



Synonyms, Omalogyra, Jeffreys; Spira, Brown; Ammoni- 

 cerina, Costa, 1861. 



Etymology, a flat circle. 



Type, H. atomus, Philippi (Skenea nitidissima, P. and H.). 



Animal with a flattened body, no tentacles ; eyes sessile, and 

 placed behind the head. 



Shell minute, forming a flat coil ; spire inyolute ; whorls 

 more or less angulated ; mouth clasping both sides of the peri- 

 phery ; operculum few-whorled, with a central nucleus. 



The upper part of the body of H. atomus is partially ciliated. 

 The tongue has only a single row of teeth, resembling miniature 

 shark's teeth. 



Distrihution, 2 species. In pools, and just beyond low water, 

 on sea-weeds and Zostera. Norway, Britain, Prance, shores of 

 the Mediterranean. 



Fossil, upper tertiary deposits. • 



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