32 
861, 2.— Oblong, rounded at both ends, nearly closed 
posteriorly, covered with raised prickly concentric 
striz, which posteriorly form rather distant radiating 
rows of prickles but not ribs; hinge margin reflected, 
covered by a single elongated accessorial plate ; a tooth 
like process on the hinge ascending obliquely and 
anteriorly. 1...2%. Common. 
P. Parva. Mont. 22.¢.1. f. 7,8.—Turt. B. p. 9. 
—F. 457.—D. p. 38.—P. DactytoipeEs. Lam. 4.— 
Ovate, posteriorly beaked and rough with reticulated 
rather prickly strie ; fold above the hinge without cells ; 
a smooth tuhercle on the inner margin above the teeth ; 
a single accessorial valve at the hinge. 3...1%. South 
Coast. 
Grenus.—XYLOPHAGA. Turton 
Globular-oval, equivalve, very open at the anterior 
side and closed behind, furnished with accessorial 
valves about the hinge. Hinge without the long 
curved tooth under the margin, no ligament. 
X. Dorsaris, Turt. B. t. 2. f. 4, 5.—Sow. G.— 
Reeve. t. 22.—F. p. 455.—Valves rounded, without 
auricles and closed behind, furnished with a longitudi- 
nal jointed rib on the inside and a corresponding ex- 
ternal groove; a triangular striated projection in the 
front of each valve. 0,40. Torbay. 
