424 
MOLLUSCA. CARDIADiE. Pholadomy^ea. 
8. C. semigranulatum.-^Gc^hose^ transverse, subtriangular, longitudinally 
striated, posterior side straight, longitudinally sulcated, and largely granu- 
lated. — Sower. Min. Conch, t. cxliv . — London Clay. 
9. C. angustatum — Transversely elongated, thin, rather depressed ; costae 
twenty- seven, margin toothed ; retrally truncated, anteally rounded — Sower. 
Min. Conch, t. cclxxxiii. f. 2 — Crag. 
10. C. edulmum . — Nearly orbicular, convex, slightly oblique, thick ; costae 
eighteen, rugose ; slightly truncated retrally — ^Sower. Min. Conch, t. cclxxxiii. 
f. 3 Crag. 
1 1. C. turgidum — Obovate, transverse, smooth, gibbose ; longitudinally 
striated retrally ; edge minutely toothed. — {Brander^ Sower. Min. 
Conch, t. cccxlvi. f. 1 — London Clay. 
12. C. porulosum — Orbicular, retrally obscurely truncated, longitudinally 
sulcated, with a row of erect, approximate spines united near their points, 
alternating with each sulcus; sulci terminated by ligulate teeth. Var. 
spines united through their whole length by a membrane, and their bases 
sunk beneath the edges of the sulci.— (.Brawder, 99.) — Sower. Min. Conch, 
t. cccxlvi. f. 2 . — London Clay. 
13. C. striatiilum.~-Oxh\c,\ihir^ convex, concentrically striated, posterior side 
longitudinally striated, with a toothed edge — Sower. Min. Conch, t. Dliii. f. 1. 
— In Lias* 
14. C. truncatum . — Transversely ovate, gibbose, smooth; posterior side 
obliquely truncated, longitudinally sulcated; beaks small — (C. pectinatum^ 
Young., and Brit. Geol. York. 22G. t. viii. £ 5.) — Soioer. Min. Conch, t. Dliii. 
f. 3. — In Lias. 
15. C. dissimile — Transversely oboyate, gibbose, smooth ; posterior side 
bounded by a small rib, longitudinally striated ; front rather straight — Sower. 
Min. Conch, t. Dliii. f. 2. — Upper Oolite. 
16. C. decussatum . — Cordiform antiquated, longitudinally ribbed, anterior 
margin rounded ; posterior side a broad area raised in the middle ; length 
and breadth nearly equal.— Geol. 126. t. xxv. f. 3. 
Gen. PliOLADOMY/EA.— A transverse, thin, subhya- 
line, veotricose slieil ; the posterior portion short, rounded ; 
the anterior more or less elongated and gaping ; hinge 
composed of an elongated subtrigonal faveola, and a mar- 
ginal plate in each valve, with a rather short external liga- 
ment ; the muscular impressions two, indistinct ; the sinus 
jn the impression of the mantel large ; the umbones ap- 
proximated.’"— 
K P. p*oc/acto.-T— Transversely oblong, gibbose, with six or seven angular 
longitudinal ridges ; produced side plain — Sower. Min. Conch, t. cxcvii. f. 1. 
— Inferior Oolite. 
2. P. ohtusa — Transversely obovate, recurved, gibbose, with from seven to 
ten longitudinal, nearly equal, tiiberculated ridges, — Sower. Min. Conch. 
t. cxcvii, £ 2 .- — Inferior Qoljte. 
