234 TURBONILLID^. 



Sy7i. — Miclielia, Ronier. Holopella, Sandb. (in part). 



Bistr. — Fossil, 75 sp. L. Silurian — Trias ; ISforth America, 

 Europe. L. costatum, Sandb. (Ixviii, 9*7). 



Shell elongated, many-whorled ; aperture simple, attenuated 

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



Like many other palaeozoic genera, the bad condition of many 

 of the species and the variation in form and sculpture render it 

 difficult to place it properly in a systematic work ; some of the 

 species might go into Turbonillidse, others appear closely allied 

 to Chemnitzia, and might even be synonj^mous with it. 



Orthonema, Meek and Worthen, 1861. 



Dist7\ — Several fossil species. Devonian, Carboniferous ; U. S. 

 0. Salteri, Meek. 



Shell elongate, many-whorled ; volutions ornamented with 

 revolving carinse, crossed by nearly straight lines of growth ; 

 body-whorl not produced below ; aperture angular above, slightly 

 effuse below ; peristome incomplete ; lip simple, nearly straight ; 

 axis imperforate. 



Differs from Turritella in its slightly effuse and less, rounded 

 aperture, disconnected peristome, and straight outer lip. It is 

 probably more nearly allied to Loxonema, but has distinct 

 revolving carinse, and wants the sigmoid outer lip of that genus. 



BouRGUETiA, Desh. 



Distr. — Phasianella striata^ Sowb., etc. Jurassic. 



Shell large, turreted ; spire long, pointed ; whorls convex, 

 spirally striated or grooved ; last whorl large ; mouth oval, 

 angular behind, widened and rounded in front. 



Family TURBONILLIDJE. 



Animal with a short head, triangular tentacles, and eyes at 

 their outer bases ; proboscis long, retractile ; foot truncated in 

 front. 



Shell white, slender, elongated, many-whorled, mostly longi- 

 tudinally ribbed or spirally striate. Operculum horny, sub- 

 spiral. 



The animal differs from that of Eulimidse and resembles that of 

 Pyramidellidse, but the shell is, in the recent species, usuallj^ 

 more slim than Pyramidella, and without columellar folds, or 

 with a single small fold. It differs from Eulima in being sculp- 

 tured. 



Most of the recent species are of quite small size. 



TURBONILLA, RisSO. 



^?/n.— Chemnitzia, d'Orb., 1839, not 1850. Pyrgiscus, Phil. 

 Orthostelis, Arad. 



