29 
T. Nana. Turt. B. p. 16. ¢.2.f. 6, 7.—F. p. 455. 
—Valves rounded and without auricles behind, a strong 
conic tooth on the margin above the teeth which points 
rather obliquely. Diam.+. Torbay. Not unlike a 
young Xylophaga, but destitute of the jointed internal 
rib, 
Famiry.—PHOLADARIA, Lam. 
Without a tubular sheath ; hinge aided by accessary 
valves, or very widely yaping posteriorly. 
Grenus.—PHOLAS, Lin. 
Transverse ; hinge margin rolled outwards ; a-rib-like 
tooth proceeding from the cavity under the beaks. 
* Valves divided by a longitudinal groove. 
P.Crispata. Lin. L1L11.—Mont. p. 23.—T. Biv.p. 
6.—Don. 3. t. 62.— Dil. 40.—Lam. 7.—Ch. f. 872,3, 
4—Oblong, rounded and gaping posteriorly ; obliquely 
truncated and open anteriorly ; posterior portion rough- 
ened by numerous thin waved concentric ridges, with 
obsolete radiating furrows; anterior portion rather 
smooth; hinge margin reflected, smooth; apophysis 
linear. 2...3. Common. 
P. Papyracea, Turton, B.2. t. 1, f. 1. to 4.—F. 
456.—Sow. G. f. 3.—Reeve, t. 24. f. 3.—Oblong ; 
