:314 MOLLUSCA. PECTINIBRANCHIA. Skenea. 



266. S. divisa. — Whorls three or four ; the upper half of 

 each smooth, the under half spirally striated. 



Turbo divisus, Adams, Linn. Trans, iii. 254.— Common from deep water. 

 Breadth scarcely a line ; white, glossy, subpellucid ; whorls round, nearly 

 on a level above, with a deep separating line ; beneath, the central cavity is 

 large, and exposes the superior volutions; aperture circular, and usually de- 

 tached from the body -whorl. 



The following Extinct Species appear to belong to this genus. 



1. S. cequalis — Equilaterally concave, with one obscure keel on the right 

 side, and two on the left ; smooth ; whorls exposed ; aperture orbicular. — 

 Sower. Min. Conch, t. cxl. f. 1. — In Carboniferous Limestone. 



2. S. concava. — Discoid, involute, flat on one side, concave on the other ; 

 whorls four, the last but slightly attached — Vermicularia con. Sower. Min. 

 Conch, t. lvii. f. 1-5. —In Green Sand. 



3. S. umbonata Discoid, involute ; umbonated above, concave beneath ; 



whorls three, the smallest concealed in the umbo — Vermicularia umb. Sower. 

 Min. Conch, t. lvii. f. G, 7 — Mr Mantell adds, that the outer volution is pro- 

 duced, and marked with distant annular ridges. — Geo]. Suss. iii. t. xviii. f. 

 24 Grey Chalk Marl. 



4. S. ovata Discoid, involute, rudely ovate, a little concave beneath ; 



whorls three. — Vermicularia ovata, Sower. Min. Conch, t. lvii. f. 8 Upper 



Oolite. 



5. S. catillus Depressed ; beneath nearly flat, above concave, somewhat 



contracted, crossed with oblique striae ; whorls three, externally broad, con- 

 vex, oblique, transversely striated, and bordered on each side by a sharp edge. 



Helix catillus, Mart. Derb. t. vii. f. 1, 2 — Euomphalus cat. Sower. Min. 



Conch, t. xlv. f. 3, 4 — In Carboniferous Limestone. 



6. S. perangulatus. — A prominent central ridge or rising angle on the up- 

 per side, within which is a flat obliquely depressed space to the separating 

 line ; the other side obtusely angulated ; striae of hair-like growth ; whorls 

 almost wholly exposed ; aperture obscurely pentangular, rounded on the outer 



side Park. Org. Rem. iii. 77- t. vi. f. 7, 8. — Euomphalus pent. Sower. Min. 



Conch, t. xlv. f. 1, 2 Carboniferous Limestone, Ireland. 



7. S.funata. — Conical, very short; with many spiral threads, united by 



more numerous transverse lines ; central cavity rather small Euomphalus 



fun. Sower. Min. Conch, t. ccccl. £ 1, 2 — Carboniferous Limestone, Dudley. 



8. S. carinata Discoid, smooth, whorls five ventricose, obtusely carinat- 



ed ; convex below, central cavity large ; aperture transverse, obovate. — 

 Cirus car. Soiver. Min. Conch, t. ccccxxix. f. 3, 4 — Lias, Cheltenham. 



Gen. EUOMPHALUS— Spire produced. 



1. E. acutus Whorls eight, conical, sharp, with an obtuse ridge near the 



upper part of each, within which there is a flat space ; aperture round. — 

 Sower Min. Conch, t. cxli. — In Carboniferous Limestone, Ireland— It is near- 

 ly related to Skenea pentangularis, from which it differs in the produced 

 spire, and in the Hat space on the top of each whorl not reaching to the 

 centre. 



2. E. rotundatus Conical, nearly smooth, whorls convex ; central cavity 



large ; aperture round. — Cirus rotundatus, Sower. Min. Conch, t. ccccxxix. f 

 I, 2.—Carbo7iiferous Limestone, Yorkshire. 



