SCALARTID^. 53 



sharp, siniini. /'/>;, Jeffreys, 1807, ' < >nym. preoc- 



cupied in Cnistn. 



:<>n IMI..I:\, A. Adams, 1^ 



Shell ninbilicated, turriculatt'd or snhul:if r ; whorls slightly 

 convex, spirally silicate, with line longitudinal stria' in the inter- 

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

 lip tree, simple. 

 Section ACT.KONEMA, Conrad, 1805. 



Shell slightly umbilicated, conical; whorls numerous; aper- 

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

 ous, sharp. Caelatura, Conrad, 1805, is a synonym. 



A. STRIATUM, Lea. Eocene of Alabama. 



Genus STILBE, Jeffreys, 1884. 



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

 sharp ; whorls numerous, 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, with 

 rather distant, siiblamellar longitudinal strue ; whorls convex; 

 mouth circular, lip continuous, thin. 



Silurian. E. SCALARIFORME, Lindstrom. 



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

 Conrad, 1873; but if the latter is really, as suspected, a syno- 

 nym of Spironema, Meek, 1804, Hall's name might be retained. 



