STREPTAXID^. 15 



than the other groups of the genus, in some species attaining a 

 length of three inches. 



SELASiELLA, Strebcl, 1818. Shell very small, glossy, vertically 

 striated ; columella truncated ; labial palpi wanting. The stomach 

 is simple as in Streptostyla (but is double in Glandina). 3 sp. 

 Mexico. 0. perpusilla, Pfeitfer. 



[PsEUDOSUBULiNA, Strcbcl and Pfeffer, 1882. 



Distr. — Mexico. F. Chiapensis, Pfeiifer. 



Shell turriculated, whorls numerous, narrow, the last much 

 smaller than the others ; columella truncated at the base ; peris- 

 tome simple. 



Animal without jaw. 



voLUTAXis, Strebel and Pfeffer, 1882. Columella with a basal 

 plication. Spiraxis Berendti^ Pfeiffer. Mexico. 



The shells resemble Subulina and Spiraxis, but th'e animal has 

 no jaw.] 



Streptostyla, Shuttleworth, 1852. 



Distr. — 49 sp. Tropical America, West Indies. 



Shell oval-oblong, subcylindrical,the last whorl proportionally 

 very large, cylindrical ; aperture elongated, narrow behind ; 

 outer lip simple, inflected in the middle; columella with a 

 thickened fold at the base. 



Animal : tentacles but slightly developed, labial palpi moderate, 

 foot short. 



The texture and general form of the shell do not much differ 

 from some species of Oleacina, but the genus is at once distin- 

 guished by its columellar fold, instead of the truncation of 

 Oleacina. 



streptostyla (restricted). Shell longitudinally striated. S. 

 Nicoleti^ Shuttl. 



CHERSOMiTRA (Shuttlcworth), Albers, 1860. Shell cjdindrical, 

 smooth, shining, usually yellowish ; aperture more than half the 

 length of the shell ; outer lip distinctly inflected. Mexico, 

 Guatemala. S. Delattrei, Pfr. (xcii, 54). Central America. 



PETENiA, Crosse and Fischer, 1868. Distinguished by the 

 presence of a muciparous pore at the end of the foot ; tentacles 

 and buccal lobes as in Glandina; foot truncated behind. Spire 

 lengthened ; columella twisted. S. ligulata^ Morelet. 



Family STREPTAXIDJS. 



Shell heliciform or pupiform, often with the last whorls 

 obliquely deviating. 



Animal with a long neck and short tail ; superior tentacles 

 long, narrow ; labial palpi narrow, moderate. 



