Family TURBONILLID.E. 



Shell minute, white, slender, elongated, many-whorled, usually 

 longitudinally or spirall}^ sculptured ; columella without plica- 

 tions or with a sinole small fold ; apex sinistral. 



Animal as in Pyramidellid;v. Operculum corneous, pauci- 

 spiral. 



The species are very small, and mostly more slender than in 

 Pyramidellidiie ; they are numerous, and have been separated 

 into a number of inferior groups, which are, for the most part, 

 poo rl}' defined — so that their classification is difficult and uncer- 

 tain. As most of these groups are founded on European 

 species, I have not, as a rule, included any extra-limital forms, 

 preferring for my purposes a geographical division of the 

 species. Hitherto the species have neither been monographed 

 nor catalogued. 



Synopsis of Genera. 



^ Genus TURBONILLA, Risso, 1826. 



Shell slender, elongated, many whorled, generally costulate, 

 apex sinistral, columella vertical, not plicate. Operculum horu}^, 

 subspiral,tlie C')luuu'llar margin entire, ftice with a spiral groove. 



Animal with wide tentacles, raentum elongated, flattened, 

 usually bilobed in front; foot large, anteriorly auriculated. 



Comprises a great number of small, graceful, usually white 

 shells; distribution universal. Fossil, tertiary. The synonyms 

 are Chemnitzia, d'Orb., 1839, not 1850; Pijrgiscus^ Philippi, 

 1841 ; Orlhostelis, Aradas. 



Section Tragula, Monts., 1884. " 



Sculpture fenestrate; spire elevated, acute, apex twisted; 

 whorls scalariform ; columella without fold or tooth. T. 



FENESTRATA, ForbcS. 



Section Trabecula, Monts., 1884. 



Whorls rounded, longitudinally lamellose ; aperture semicir- 

 cular, with an exterior rib; no apparent spiral sculpture; apex 



(317) 



