B14 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. cmcava Discoid, involute, flat on one side, concave on the other ; 
whorls four, the last but slightly attached — Vermicularia con. Sower. Min. 
Conch, t. Ivii. f. 1—5. — In Green Sand. 
3. S. umhonata Discoid, involute ; umbonated above, concave beneath ; 
whorls three, the smallest concealed in the umbo — Vermicularia umb. Sower. 
Min. Conch, t. Ivii. f. 6, 7* — Mr Mantell adds, that the outer volution is pro- 
duced, and marked with distant annular ridges — Geol. Suss. iii. t. xviii. f. 
24 Grey Chalk Marl. 
4. S. ovata Discoid, immlute, rudely ovate, a little concave beneath ; 
whorls three. — Vermicularia ovata. Sower. Min. Conch, t. Ivii. 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 w'hich 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. Hem. 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 ; wdth many spiral threads, united by 
more numerous transverse lines ; central cavity rather small — Euomphalus 
fun. Sower. Min. Conch, t. ccccl. f. 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. Sower. Min. Conch, t. ccccxxix. f. 3, 4 — Lias, Cheltenham. 
Oen. euomphalus. — S pire 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 flat 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, ‘^.--’-Carboniferous Limestone, Yorkshire. 
