TRIBIO PHOLADARTA. 



TRIBE PIIOLADARIA. 



Devoid of a tubular sheath: valves with accessory pieces or 

 considerably 'japing posteriorly . 



PHOLAS. 



Shell bivalve, cqui valve, transverse, gaping at both extremities, with 

 various accessory pieces either on the hinge or below it, ; inferior 

 margin of the valves infected. 



* Valves not divided by a radiating groove. 



P. Dactylus.* Lin. \U0.— D.p. 35.— Ch.f. 859.—E.L 168. 

 /. 2, 3, 4.— Lam. I.— Don. t. 118.— B. t. l.f.7.—Sow. G.— 

 'Reeve, t. 24. /. \.— Wood. G. C. t. \3.-TurL B. p. 8.— Mont. 

 p. 20. — W. t. 2. f. 1. Elongated-oblong, beaked at one end and 

 rounded at the other, with concentric waved muricated ridges and 

 indistinct radiating striae towards the beaks ; margin above the 

 umbones reflected, circular and supported by numerous small plates 

 so as to form quadrangular cells : 4 accessory plates. 4 or 5. 

 — Europe.* 



P. Orientalis. Gmel. 3216.— D. p. 36.— Lam. 2.— Ch. f 

 860 — W. t. 2.f. 2. Elongated-oblong, white, brittle, and nearly 

 closed at one end, one half of each valve smooth and the other 

 marked with reticulated striae ; margin straight. 1^ .. 6. — Siamand 

 Tranquebar. Somewhat resembles the last but is not beahed. 



P. Candida.* Lin. 1111 . — D. p. 36.— Lam. 3.— W. t.2.f.3. 

 Don. t. 132.— Ch.f. 861, 2.— Wood. G. C. t. 14. /. 3, 4. Oblong, 

 rounded at both ends, ventral margin entirely convex and not at all 

 indented, covered with decussated prickly striae which posteriorly 

 form distant radiating rows of prickles (but not ribs) : margin above 

 the hinge reflected and covered with an elongated accessorial plate : 

 a toothlike process on the hinge, ascending obliquely and anteriorly. 

 % . . 2. — Europe. 



P. Parva.* Mont. p. 22. t. \.f. 7, 8.—D.p. 38.— W. t. 2.f. 6. 

 — Tart. Biv. p. 9. — P. Dactyloides, Lam. 4 . Ovate, beaked poste- 

 riorly, rough with reticulated rather prickly striae except anteriorly ; 



2 P. Oblongata Say is probably this species, although its beak 

 and the number of its accessory valves is not mentioned. 



P. Callosa. Lain. 8. Ovate-oblong, sinuated, posteriorly with 

 curling striae, anteriorly smooth ; hinge plate rather prominent and 

 globose. — Bayonne. From, the brevity of this description, lam 

 unable to recognize the species, the figures quoted by Deshayes 

 however (List. t. 433. and Brooke, t. \. f. 7, 8.) are distorted 

 Daciyli. 



