GASTEROPODA. 313 



aperture long and narrow; columella plaited; sometimes 

 operculated. 



Animal with a flattened, disk-like head, and broad obtuse 

 tentacles ; foot ample, furnished with lateral and operculigerous 

 lobes. 



The shells of this family are chiefly extinct, ranging from the 

 period of the coal strata, and attaining their greatest develop- 

 ment in the cretaceous age. Tornatella is essentially related to 

 Bulla, but presents some resemblance to the FyramidelUdce in 

 its plaited and operculated aperture ; in Tornatina the nucleus, 

 or apex, is sinistral. The spiral striae which ornament many 

 of the species are punctate, as in the Bullidae ; and the outer 

 lip often remarkably thickened, as in Auricula. 



Tornatella, Lamarck. 



Type, T. tornatilis, PI. XIY., Fig. 1. 



Synonyms, Actseon, Montf. (not Oken), Dactylus (solidulus), 

 Schum. ? Monoptygma (elegans), Lea. 



Shell solid, ovate, with a conical, many-whorled spire ; 



Fig. 137. 



spirally grooved or punctate-striate ; aperture long, narrow, 

 rounded in front ; outer lip sharp ; columella with a strong, 

 tortuous fold ; operculum horny, elliptical, lamellar. 



Animal white ; head truncated and slightly notched in front, 

 furnished posteriorly with recumbent tentacular lobes, and 

 small eyes near their inner bases; foot oblong, lateral lobes 

 slightly reflected on the shell. Lingual teeth 12.12, similar, 

 with long simple hooks. 



Distribution, 16 species. United States, Britain, Senegal, 

 Eed Sea, Philippines, Japan, Peru. T. tornatilis inhabits deep 

 water — 60 fathoms. (Porbes.) 



jFoss'i7, 70 species. Trias — Lias— ^. North America, Europe, 

 South India. 



Sub-genera. Cylindrites (Llhwyd), Lycett. 0. acutus, Sby. 

 PI. XIY., Pig. 2. (A.) Shell smooth, slender, sub -cylindrical, 

 spire small, aperture long and narrow, columella rounded, 



P 



