SCALARIID-^. 53 



sharp, sinuous. 3Ienippe, Jeffreys, 1861, is a synonym, preoc- 

 cupied in Crustacea. 

 Section loLiEA, A. Adams, 1860. 



Sliell urabilicated, turriculated or subulate; Avliorls slightly 

 convex, spirally sulcate, with fine longitudinal striae in the inter- 

 stices ; aperture oblong, acuminated behind, rounded in front, 

 lip free, simple. 

 Section Act^onema, Conrad, 1865. 



Shell slightl}^ umbilicated, conical; whorls numerous; aper- 

 ture suboval, rounded and reflected at the base, lip not continu- 

 ous, sharp. Cselatura, Conrad, 1865, is a synonym. 



A. STRIATUM, Lea. Eocene of Alabama. 



Genus STILBE, Jeffreys, 1884. 



Shell conical, elongated, smooth, shining, apex regular and 

 sharp ; whorls numei'ous, but slightly convex ; aperture sub- 

 oval, angulated in front and behind, lip sharp. Atlantic Ocean; 

 abyssal. 



Jeffreys has placed this group in Turritellidse ; it appears to 

 be more nearly related to Aclis. 



Genus HOLOPELLA, M'Coy, 1852. 



Shell elongated, slender, of numerous gradually increasing 

 convex whorls, with deep suture, usually arcuately striate, or 

 smooth, sometimes reticulated ; aperture circular, with contin- 

 uous peristome ; base rounded, with or without a minute umbili- 

 cus 



Silurian-Triassic. H. gregaria, Sowb. 



About a dozen species are known. Aclisina, de Koninck, 

 1881, is a synonym. 



? Genus ELASMONEMA, Fischer, 1885. 



Shell sometimes elongated, sometimes short or globular, Avith 

 ratlier distant, sublamellar longitudinal striae ; whorls convex ; 

 mouth circular, lip continuous, thin. 



Silurian. E. Scalariforme, Lindstrom. 



Tlie name is proposed instead of Callonema, Hall, 1879, not 

 Conrad, 18Y3; but if the latter is really, as suspected, a sj-no- 

 nym of Spironema, Meek, 1864, Hall's name might be retained. 



