32 



861, 2. Oblong, rounded at both ends, nearly closed 

 posteriorly, covered with raised prickly concentric 

 striae, 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. *.!./. 7, S.Turt. B.p. 9. 

 F. 457. D. p. 38. P. DACTYLOIDES. Lam. 4. 

 Ovate, posteriorly beaked and rough with reticulated 

 rather prickly striae ; fold above the hinge without cells ; 

 a smooth tubercle on the inner margin above the teeth ; 

 a single accessorial valve at the hinge. I...1L South 

 Coast. 



GENUS. 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. DORSALIS, Turt. B. t. 2. /. 4, 6. Saw. 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. 



