172 SUPPLEMENT. 



edges, which are plain : tubes almost sessile, obliquely trun- 

 cated towards the front of the shell; upper one much the 

 smaller ; lower one not well defined, and scarcely separated 

 from the folds of the mantle on the postico-ventral side ; 

 orifices thickly studded with flake-white tubercles or papillae : 

 foot vermicular, and pointed at the end : gills consisting of 

 2 pairs, the outer of which is much larger than the other and 

 enwraps it. 



F. Errol (Crosskey) ! ; Labrador, Canada, and Maine. E. 

 Holland (Herklots) ; Sea of Okhotsk, Wellington Channel, and 

 Labrador. M. striatida, Beck. 



P. 131. — Crenellarhombea. Cornwall (Hockin); Bundoran 

 (Waller) ! F. Antwerp Crag (Nyst) ! E. Naples (Stefanis) ! 



P. 133. — C. decussata. Ligament wholly internal, elon- 

 gated, and covering a great part of the hinge-plate. N. of 

 Hebr., 189 and 530 f. (C. and T.). F. Norway. E. Lof- 

 foden I., 300 f. (Sars); Gaspe Bay, Gulf of St. Lawrence 

 (Whiteaves) ! 



P. 135. — Modiola cuprea is the fry of C. faba. 



P. 141. — Nucul a sulcata. F. Caithness (Peach) ! ; N. W. 

 Germany, and Italy. E. Atlantic coasts of France ! 



p. 143.— N. hucleus. N. of Hebr., 530 f. (C. and T.). F. 

 Scandinavia, Belgium, and N.W. Germany. 



P. 149. — N. N1TIDA. 



Body whitish : mantle slightly extending beyond the valves ; 

 margin closely fringed with short cilia : tubes inconspicuous : 

 foot tongue-shaped ; when protruded, it unfolds like the leaf 

 of a fan-palm, and displays a beautiful comb-like fringe at its 

 edges ; the sole then assumes an oval shape, and the pectina- 

 tions diminish in size towards its point or extremity, and are 

 larger at its sides. 



E. Atlantic coasts of France, and throughout the Mediter- 

 ranean ! 



P. 151.— N. tenuis. N. of Hebr., 189-650 f. (C. and T.). 

 F. Scandinavia, S. Italy, and Canada. E. Brittany (Cailliaud 

 and Tasle); Algeria (coll. M'Andrew) ! ; Corsica and Naples 

 (Tiberi and others) !; iEgean (Forbes) ; N. Asia and W. coast 

 of N. America (P. Carpenter). N. cegeensis, Forbes, and N. 

 Macandrwi, Hanley, from the types. 



