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Show 670 DR. GWYN JEFFREYS ON THE MOLLUSCA OF THE [Nov. 14, rocks and stones. C Verd I. (de Rochebrune). Not Arctic, nor Asiatic, nor American. Fossil. Pliocene : Red Crag. Post-tertiary, especially in raised sea-beaches : Scandinavia, Great Britain and Ireland, France, and Italy; 0-1360 ft. An extremely variable species, as regards shape, size, position of the apex, sculpture, colour, inner coating, habitat, and every other characteristic than that of being conical. All the North-Atlantic so-called species, except P. ferruginea or saflana, but including the varieties noticed in ' British Conchology' and P. lusitanica of Gmelin or punctata of Lamarck, run one into another by insensible gradations. Although the following more properly relates to the habits of the Mammalia than to those of the Mollusca, it is not devoid of interest in this place. In a letter from Dr. Fleming to Prof. Jamieson (Mem. Wern. Soc. 1823), he says that at Scalpa, "in the course of conversation with the keeper of the lighthouse Mr. Reid, a judicious observing man, I was informed that rats (the brown or Norway rat, which abounds in the Hebrides) after a shower go down upon the rocks, while the Limpets are crawling about, and by a sudden jerk with their noses detach them from the rocks for food. Should the first effort fail, another is never attempted against the same individual, now warned and adhering closely to the rock ; but the rat proceeds instantly to others still off their guard, until enough of food has been procured." See also an interesting paper by Mr. J. Clark Hawkshaw on the habits of the Common Limpet in the ' Journal of the Linnean Society' (Zoology) for 1878. As may be expected, the synonyms are numerous, and include P. vulgaris of Belon, whose name is older than that of Linne by about two centuries. HELCION PELLUCIDUM, Linne. Patella pellucida, L. S. N. p. 1260. H. pellucidum, B. C. iii. p. 242, pl. v. f. 4; v. p. 199, pl. lviii. f. 1, 2. ' Porcupine' Exp. 1869 : St. Donegal B. 1870 : Atl. Vigo B. Distribution. Iceland, Faroe I., N. Cape to Mogador, Mediterranean (Linne) ? Antibes (Martin, f. Petit) 1; 0-20 fms., usually on Laminaria. Fossil. Pliocene: Sicily (Seguenza). Post-tertiary: Norway, Scotland, and N. Ireland; 0-130 ft. In the 'Philosophical Transactions' for 1696 Sir Robert Sibbald mentioned this as the " Oval Limpet" in his letter to Dr. Lister on Skye shells. There are at least half a dozen synonyms. Ou the other hand, Cantraine thought it very possible that Helcion pellucidum, Tectura virginea, and Gadinia gussoni (the last being his Patelloidea vitrea) belong to one and the same species ! Lamarck gives the type of the present genus (Helcion pectinatum) as Mediterranean on the authority of Born. |