GASTEEOPODA. 241 



Animal with a long retractile proboscis ; tentacles close' 

 together, slender, inflated at the tij)S ; eyes immersed at the 

 bases of the tentacles ; operculum lobe ample, unsymmetrical ; 

 foot truncated in front. Eanges to 80 fathoms water. 5 British 

 species, Norway. 



Fossil. ? species. Pliocene — . Britain (Crag). 



Sttloptygma, Adams. 1860. 



Shell pupiform, semi-transparent; with slightly convex whorls. 

 Aperture sub -quadrate. 



Mtonia, Adams. 



Shell ovate, turreted ; white, thin, with slightly convex 

 whorls. Aperture oblong. 



Letjcotina, Adams. 



Shell like last, but with last whorl ventricose ; with minute 

 dots. 



Stilifee,, Brod. 



Example^ S. astericola. PL YIIL, Pig. 15. 



Synonym, Stylina, Pleming. 



Shell hyaline, globular or subulate, apex tapering, styliform, 

 nucleus sinistral. 



Animal with slender, cylindrical tentacles, and small sessile 

 eyes at their outer bases ; mantle thick, reflected over the last 

 whorls of the shell ; foot large, with a frontal lobe. Branchial 

 plume single. Attached to the spines of sea-urchins, or immersed 

 in living star-fishes and corals. 



Distribution^ 16 species. West Indies, Britain, Philippines, 

 Gallapagos, Pacific. 



LoxoNEMA, Phillips. 



Etymology^ loxos^ oblique, and nema, thread ; in allusion to 

 the striated surface of many species. 



Type, L. sinuata, U. Devonian, Petherwin. 



Shell elongated, many-whorled ; aperture simple, attenuated 

 above, effused below, with a sigmoidal edge to the outer lip. 



Fossil, 75 species. L. silurian — Trias. North America, Europe. 



Maceocheilus, Phillips. 



Etymology, macros, long, and cheilos, lip. 

 Synonym, Polyphemopsis, Portlock. 



Shell thick, ventricose, buccinoid; aperture simple, effuse 



M 



