T. NANA. Turt.B. p. 16. t. 2./. 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. i. Torbay. Not unlike a 

 young Xylophaga, but destitute of the jointed internal 

 rib. 



FAMILY. PHOLADARIA, LAM. 

 Without a tubular sheath ; hinge aided by accessary 

 valves, or very widely y aping posteriorly. 



GENUS. 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. IIII. Mont. p. 23. T. Biv.p. 

 6. Don. 3. t. 62.DU. 40. Lam. l.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.Z. t. I./. 1. to4.F. 

 456.Sow. G. /. 3. Reeve, t. 24. /. 3. Oblong ; 



