336 CCELIAXIS. 



similar hollow axis. Distceckia cannot, however, be regarded 

 as ancestral to the recent genera, since by its free last whorl 

 and collared peris-tome the Eocene genus is obviously already 

 a senile phylum. The Eocene of western Europe, like the 

 modern Antillean fauna, contained many senile types of land 

 snails, which left no descendants. 



The name proposed by Crosse for this genus suffered some 

 mutilation at the hands of Messrs. Harris and Burrows, who 

 also added the synonym Spartina. Both names were used by 

 them " Distcectria (Spartina) parisiensis Desh. " for the 

 one species in their first reference (t. c., p. 100), so that their 

 subsequent statement (pp. 113, 114) that the new names were 

 intended as substitutes for Cylindrella and Thaumasia, re- 

 spectively, cannot affect their true status as synonymous 

 terms applying to the species parisiensis. 



Genus CCELIAXIS Adams and Angas. 



Cceliaxis AD. and ANG., Proe. Zool. Soc. Lond., 1865, p. 54, 

 based upon C. layarcbi only. PILSBRY, Man. Conch., xvi, 194. 

 Bathyaxis ANCEY, Concholo gist's Exchange, ii, p. 39 (Sep- 

 tember, 1887), same type. Sphalerostoma GIRARD, Jornal de 

 Sciencias Math., Phys. e Nat. Acad. Real Sci. de Lisboa (2 

 ser.), ii, p. 247 (1892), same type. 



Shell umbilicate, long, turrite, composed of many (about 

 20) closely coiled whorls; the upper half attenuate, apex 

 rounded, rather large, the first whorl smooth, the rest ver- 

 tically rib-striate. Early whorls sometimes lost in the adult 

 shell. Aperture small, ovate, the blunt lip slightly expanded, 

 columellar lip rolled back. Axis hollow, tubular and straight, 

 encircled by a single cord-like lamella below the middle in 

 each whorl in adult shells, terminating in a small columellar 

 fold. Young with strong, spiral, parietal and basal lamellae 

 and an oblique columellar barrier in the antepenult, whorl. 



Jaw highly arched, and either very weakly ribbed (plaited) 

 or with sparse striae. Radula (pi. 51, figs. 7, 8) with 21, 1, 21 

 teeth in slightly, regularly arcuate rows. Middle tooth nar- 

 row, less than half the width of the adjacent laterals, with a 

 short, simple cusp. Laterals having a large mesocone and 



