SUPPLEMENT. 173 



P. 154. — Leda PYGMiEA. F. Scandinavia and Maine. E. 

 LofFoden I., 300 f. (Sars) ; Gulf of Gascony, 40-80 f. (Marquis 

 de Folin, /. Fischer, as L. tenuis) ! ; Gulf of Naples and Sicily, 

 50-60 f. C Acton and Stefanis) ! The recent discovery of this and 

 other species hitherto considered northern in the Bay of Biscay, 

 as well as in the Mediterranean, confirms the suggestion which 

 I threw out in my last Eeport to the British Association on 

 Shetland dredgings, that at some former period there existed a 

 communication between the North Atlantic and the Mediter- 

 ranean, by which the submarine fauna became diffused. The 

 only objection to the hypothesis seemed to be the want of proof 

 that these species had been found in any intermediate locality. 

 I have given the size as too great; it should be 1 line in 

 length by 1| in breadth. 



P. 155. — L. LTj'ciDA*, Loven (Toldia lucida, Lov. Ind. Moll. 

 Scand. p. 34). 



Shell more than twice the size of L. pi/r/jncea, thinner, 

 rather depressed instead of tumid or gibbous, and less equila- 

 teral ; the dorsal margin on the anterior side slopes very gra- 

 dually (and not abruptly as in that species) ; and the corre- 

 sponding margin on the posterior side is more inclined to be 

 straight, and in some specimens is a little raised and pinched in 

 near the beak ; the posterior side is depressed, broad, angular, 

 and obliquely truncated. L. 0-15. B. 0-2. 



Habitat : N. of Hebr., 189-650 f. (C. and T.). Some of 

 these localities may be considered British, being much nearer to 

 Scotland than to the Faroe Isles. F. Clyde Beds (Crosskey 

 and Robertson) ! ; Norway (Sars) ; Calabria (Philippi, as Nu- 

 cula pellucida). E. Boh. — Finm. (Loven) ! ; Upper Norway, 

 10-160 f. (M^'^ndrew and Barrett)! It may be the Nucula 

 navicular is of Couthouy, from the Massachusetts coast. Toldia 

 nana of Sars, from 300 f. in the Loff'oden Isles, appears to be 

 a small variety. 



P. 155. — L. MiNUTA. F. Scandinavia, Labrador, and Ca- 

 nada ; not our Crag. E. W. coast of N. America (P. Car- 

 penter). 



P. 158. — L. PEENULA. Loch Duich in Rosshire, and St. 



* Shining. 



