224 



Costte stout, lii-je feeble ; pullus pyrtamidal, 

 whorls convex. 21. S. cylindracea. 



Whorls shouldered, trilirate in front, smootli 

 behind ; pullus subcylindrical. 



22. aS'. gonioides. 

 Costse lanielliform and crowded. 



23. S. crebrelamellata. 

 9. Periphery rounded ; aperture oval ; shell stout, costated, 



lirate and variced [HemiacirsaJ. 

 Costie and lirce few and stout. 24. S. Jampra. 



Cost?e and lira3 more numerous, slender. 



25. S. polynema. 



1. Sealaria (Clathpus) interstriata, n^. nor. 



Shell turrited, small, slender, acute, thin, translucent, imper- 

 forate; ordinary whorls eight, convex, separated by a deep suture; 

 nuclear whorls three, smooth, gradually attenuate to the tip. 



The transverse ornament consists of thin, moderately elevated, 

 oblique lamelhe which are continuous from whorl to whorl; there 

 are 17 to each of the anterior whorls. Varices absent. The spiral 

 sculpture consists of intercostal incised lines. 



Aperture circular ; peristome entire ; outer lip thin, reflected, 

 formed by the last costal-lamella. Base convex, traversed by the 

 cost», without a basal keel or funicular rib. 



Dimensions. — Length, 11; width, 3; diameter of aperture, 2. 



Locality. — Eocene ; Muddy Creek (/. Dennant ; very rare). 



This is the oldest-known species of the subgenus, which accord- 

 ing to M. de Boury did not appear till the Miocene ; from the 

 Italian Miocene and Pliocene species, it is distinguished by its 

 more numerous and thin costse. If we admit the subgenus 

 Hycdoscala, De Boury (1890), which includes the thin and trans- 

 parent species of Clathrus, then our fossil has few alliances, it 

 most resembles the elate variety of S. Jukesiana, which has, how- 

 ever, no intercostal spiral striations. 



2. Sealaria (Nodiseala) basinodosa, ^per. nor. 



Shell very small, slender, acute, solid, imperforate, with six 

 ordinary whorls and two and a half smooth shining rounded 

 nuclear whorls. 



Spire-whorls slightly convex, with an angulated profile by 

 reason of the medial enlargement of the costa?. The spiral orna- 

 ment consists of crowded punctated engraved lines, and a narrow 

 band, crenated on the margin, at the anterior edge of the suture 

 to which it is closely appressed. The transverse ornament con- 

 sists of slightly angular and medially thickened ribs (12 on the 

 penultimate whorl), which do not reach the posterior suture ; on 



