370 FERTISSACIDJE. 



siderably larger, in having a wider base, and the whorls increase 

 less rapidly at first, while the basal margin of the aperture is more 

 curved. 



Genus COILOSTELE, Benson. 



Coilostele, Benson, A. M. N. H. ser. 3, xiii, 1864, p. 136 ; Pilsbry, 



Man. Conch, ser. 2, xix, J908, p. 338. 

 Ccelostele, Blanford, J. A. S. B. xlv, 1875, p. 42. 

 Ccelestele, Bourguignat, Descr. div. Esp. Ccelestele et Pafadilhia, 1880, 



p. 6. 



TYPE, C. scalaris, Benson. 



Range. India, Aden, Syria, Abyssinia, Egypt, Southern Spain. 

 Mexico (? introduced). 



" Shell minute (3 to 4 ram. long), fragile, somewhat transparent, 

 imperforate, long and narrow, subcylindric, or tapering slightly to 

 the very obtuse rounded summit, composed of 6 to 8 flattened 

 whorls separated by deep sutures, the first 2| or 3 whorls smooth, 

 the rest either smooth, striate, or ribbed. Aperture small, oblong, 

 more or less oblique, the outer lip usually expanded slightly in 

 fully adult shells, straight in profile. Columella having a low 

 fold at its junction with the parietal wall. Internal jxirf&tbnj 

 absorbed in adult shells, leaving only the internal spiral cord along 

 the sutures. Soft anatomy unknown. 



" A genus of uncertain position, remarkable for the cylindrical 

 shape of the minute, fragile, slender shell, and the absorption of 

 the internal partitions, which I have verified in C. tampicolensis. 

 They have been found up to this time only as dead shells in the 

 drift debris of rivers and streams, where they occur in great pro- 

 fusion though it seems quite locally. Nothing is known of the 

 life-history or soft parts.'* (Pilsbry.} 



The genus has a rather remarkable distribution. The occur- 

 rence, however, in Mexico of a single species may be due to 

 importation from Spain, as suggested by Prof. Pilsbry. A fossil 

 species from the Eocene of Italy has been referred to Coilostele *, 

 and, if correctly so assigned, the centre of the distribution of the 

 genus may possibly be that region. 



342. Coilostele scalaris, Benson. 



Coilostele scalaris, Benson, A. M. N. H. ser. 3, xiii, 1864, p. 136 ; 



Hanley & Theobald, Conch. Ind. 1876, pi. 156, fig. 5 ; Pilsbry, 



Man. Conch, ser. 2, xix, 1908, p. 339, pi. 50, fig. 3. 

 Ccelostele scalaris, Blanford, J. A. S. B. xlv, 1875, p. 42 ; Theobald, 



op. cit. xlvii, 1878, p. 147 ; Nevill, Hand List, i, 1878, p. 162 ; 



Try on, Struct. Syst. Conch, iii, 1884, p. 95, pi. 102, fig. 79. 

 Ccelestele scalaris, Bourguignat, Descr. div. Esp. Ccelestele et Pala- 



dilhia, 1880, p. 10. 



* Coelostele eocaena, Oppenheim, Zeits. Dents. Geol. Gesells. xlvii, 1895, 

 p. 119, pi. 3, fig. 10. 



