104 



incurved and approximate ; inside white or whitish ; 

 epidermis velvety. If. W. Coasts. 



P. DECUSSATUS. Turt. B. p. 173. t. 12. f. 5.F. 



p. 400. Orbicular, depressed, with numerous fine 

 raised decussated lines which are clothed with a short 

 silky brown pile, yellowish white with purple and crim- 

 son clouded patches, which are often disposed in ziczac 

 angles ; inside glossy white, the disc often stained with 

 dark red, margin very strongly serrated. 1 . British 

 Channel. 



P. NUMMARIUS. Turt. B.p. 174. t. 12. /. 6.F. 

 p. 400. ARCAN. Lin. 1143? Zw*. t. 239./.81. 

 Lenticular, very finely decussated, yellowish white or 

 cream-color, with numerous round red dots (which very 

 rarely become confluent about the margin and form 

 short lines) ; beaks tumid and prominent, causing the 

 margin on each side of them to appear a little projecting 

 or as it were slightly eared like a Pec ten. i. Guernsey 

 and Torbay. 



GENUS. NUCULAr 



Oval- triangular or oblong, equivalve, inequilateral, 

 closed; the beaks approximated : hinge with an 

 oblique projecting spoon-shaped tooth in each valve, 



