324 
MOLLUSCA. TROCHUSIDJE. 
Trochus. 
EXTINCT SPECIES. 
1. T. agglutinans^ — Depressed, conical, smooth ; base expanded, with a 
broad waved margin ; whorls externally deformed ; pillar-cavity plicate ; 
aperture oblong. — (T. umbilicaris, Brander^ Foss. Hant. f. 4-5.) — Sower. Min. 
Conch, t. xcviii. — Smaller figure. — London Clay. 
2. T. Benettice — Depressed, conical ; upper surface obliquely wrinkled ; 
base expanded, with a broad waved margin ; whorls externally irregular ^ 
pillar-cavity plicate, partly covered ; aperture narrow. — Sower. Min. Conch, 
t. xcviii. — Larger figure. — London Clay. 
3. T. anylicus. — Conical, base rather convex ; volutions squarish, with tu- 
bercles upon their angles, transversely carino-striate, and a rounding eleva- 
tion in their centres ; lines of growth decussating the three central strise ; 
pillar imperforate — List. Conch, t. MDcccxxxvi. f. 16. Sower. Min. Conch, t. 
cxlii. — Lias. 
4. T. Iwvigatus — Conical, nearly smooth ; sides straight ; base convex, with 
an obtuse margin ; aperture rhomboidal, with rounded angles ; no pillar cavi- 
ty. — Sower. Min. Conch, t. clxxxi. f. 1 — Crag. 
5. T. similes. — Conical, sides straight, ornamented with many transverse 
ridges, two or three of which upon each whorl are granulated ; base flattish, 
concentrically striated ; aperture quadrangular ; pillar direct — Sower. Min. 
Conch, t. clxxxi. f. 2. — Crag. 
6. T. angulatus. — Conical, sides of the whorls concave ; base flattish ; mar- 
gin carinated ; aperture acutely rhomboidal ; no pillar cavity. — Sower. Min. 
Conch, t. clxxxi. f. 3. — Inferior Oolite. 
7. T. duplicahis, — Conical, sides of the whorls concave ; a double deeply 
crenulated carina round the base ; pillar cavity open, with a tubercular mar- 
gin ; aperture quadrangular — Sower. Min. Conch, t. clxxxi. f. 5. — Under Oolite. 
8. T. dimidiatus. — Conical, base convex, with a carinated margin ; upper 
part of the ivhorl concave, with an entire carina in the middle ; aperture pent- 
angular; pillar direct and solid —-5'ower. Min. Conch, t. clxxxi. f. 4. — Under 
Oolite. 
9. T. punctatus. — Conical, with straight sides, transversely striated ; upper 
striae upon each whorl crossed by oblique undulations ; lower ones minutely 
granulated ; a narrow band between the two sets — Sower. Min. Conch, t. cxciii. 
f. 1. — Inferior Oolite^ 
10. T. elongatus — Conical, elongated, transversely striated ; striae near the 
apex granulated ; each whorl slightly undulated near the upper edge, with an 
obscure band before the middle ; the inferior margin prominent Sower. Min. 
Conch, t. cxciii. f. 234.— /w/ereor Oolite. 
11. T. ahhreviatus — Conical shortened, transversely striated ; striae obscure- 
ly decussated by oblique lines of growth ; inferior margin of each whorl very 
prominent, obtuse, with an obscure band above it. — Sower. Min. Conch, t. 
cxciii. f. 5. — Inferior Oolite. 
12. 'T.fasciatus — Conical, umbilicate, decussate striated; whorls slightly 
convex, with a band around their middle ; base flattish ; aperture quadrangu- 
lar. — Sower. Min. Conch, t. ccxx. f. 1. — Inferior Oolite. 
13. T. arenosus — Conical, very short, granulated, whorls rather convex 
above, with a band along the middle ; base convex, in part nearly smooth. 
—Soiver. Min. Conch, t. ccxx. f. 2.-^Inferior Oolite. 
14. T. promme/w.— Conical, short, whorls convex, finely striated, with a 
