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Show 266 DR. GWYN JEFFREYS ON THE MOLLUSCA OF THE [Nov. 14, 3. SIPHODENTALIUM LOFOTENSE, M. Sars. Siphonodenlalium lofotense, M. Sars, Christ. Vid. Selsk. Forh. 1864, p. 297, t. vi. f. 29-33 : B. C. v. p. 195, pl. ci. f. 2. 'Porcupine'Exp. 1869: St. 2,6, 10, 14, 16, 18, 23, 25, 28, 1870 : Atl. 9, Vigo B., 26-30 ; Med. 50, 55. Distribution. Norway, Shetland and the Hebrides, Bay of Biscay, throughout the Mediterranean from Marseilles to the coast of Syria, 'Valorous' Exp., N e w England ; 30-1750 fms. Fossil. Pliocene: Calabria and Sicily. An undescribed species, allied to S. lofotense, was dredged by the late Mr. McAndrew in the Gulf of Suez; it differs in the mouth being encircled by a rim and in the base being bifid instead of merely notched. 4. SIPHODENTALIUM QUINQUANGULARE, Forbes. Dentalium quinquangulare, Forb. Rep. iEg. Inv. p. 188. Siphonentalis tetragona, G. O. Sars, Moll. reg. arct. Norv. p. 105, t. 20. f. 13, a-c. ' Porcupine ' Exp. 1869 : St. 3, 14, 15, 17, 38. 1870 : Atl. 1, 2, 3, 3a, 6, 8, 9, 13, 17a, 24-34 ; Med. 45, 55, Adventure Bank. Distribution. Norway, Bay of Biscay and N. Spain, Mediterranean from Algiers and Marseilles to the iEgean, Jamaica, Barbadoes, var. off Culebra I. (' Challenger' Exp.); 5-650 fms. Fossil. Pliocene : S. Italy and Sicily. I do not consider this the Dentalium tetragonum of Broechi or a variety of it, to which his and Gmelin's D. sexangulum (not D. sex-angulare of Lamarck and Deshayes) apparently belongs. Specimens of Brocchi's species from the Subapennine Tertiaries, for which I am indebted to the kindness of Professor Bellardi and the late Signor Lawley, are clearly a species of Dentalium, and have the base (or apex, whichever it may be called) truncated and fitted with a central short pipe as in D. dentalis and allied species. Some of these specimens are four-angled, while others have 5 or 6 angles. I am not at all satisfied with the generic place of this peculiar shell. The sculpture is that of most species of Dentalium, and the fry have also a bulbous or pear-shaped base; but the terminal notches, usually one on each side, agree with those in most species of Siphodentalium. Some Norwegian specimens have five notches, and are jagged like S. vitreum. If the position of these terminal notches or slits constitutes a generic character, D. subterfissum and D. rubescens ought to be separated from Dentalium with much greater reason than Antalis. Although the present species is so common in Norway and the west of Ireland, as well as southwards to the Mediterranean, it has strangely enough not yet occurred in Shetland, where the conditions of habitability are similar. 5. SIPHODENTALIUM VITREUM, M. Sars. Dentalium vitreum, M. Sars, Nyt Mag. Naturvid. 1851, Bd. vi. p. 178 (Siphonodentalium), 1858. |
