OCR Text |
Show 940 DR. GWYN JEFFREYS ON THE MOLLUSCA OF THE [Nov. 29, right valve, that on the posterior side extending through the middle of the rostrum : inside polished : scars strongly marked on the posterior side. L. 0*275, B. 0*35. 'Porcupine'Exp. 1870: Atl. St. 16,17, 17a, 22, 31-34. Several valves and a small living specimen. Distribution. Off Josephine Bank and the Azores ('Josephine' Exp.), G. Mexico; 138-790 fms. 10. NE^ERA DEPRESSA1, Jeffreys. (Plate LXXI. fig. 3.) S H E L L oval, wedge-shaped on the posterior side, depressed or somewhat flattened, thin, semitransparent, rather glossy : sculpture, fine and close-set minute concentric strise in front and on the rostrum, besides occasional lines of growth : colour whitish : epidermis filmy, apparent only on the front edge and rostrum : margins rounded on the anterior side and more gently curved in front; rostrum wedge-shaped, not defined by any indentation, somewhat truncated at the extremity; dorsal margin raised and parallel with the beak on the anterior side, sloping and slightly incurved on the other side : Beaks blunt, scarcely incurved ; umbones small and not very prominent: cartilage-pit small, obliquely projecting inwards, and resembling a tooth: hinge-line curved on the anterior and sloping ou the other side : hinge-plate thickened near the beak on each side: teeth, a single laminar lateral on the posterior side of the right valve, nearly parallel with the hinge-plate : inside glossy : scar of the posterior adductor muscle acutangular, defined beneath bv a ridge. L. 0*2, B. 0*3. 'Porcupine' Exp. 1870: Atl. St. 16, 17, 17a. Numerous valves. Differs from N. exigua in not being globose, having close-set concentric strise in front and on the posterior side, and in the rostrum being angulated and straight. The lateral tooth also is quite different ; and the ridge which defines the posterior adductor muscle in the present species is characteristic. B. Striated concentrically. AULACOPHORA. 11. N E ^ E R A L A M E L L O S A , M. Sars. N. lamellosa, M. Sars, Arct. Molluskf. v. Norges nordli°-e Kvst (1858), p. 62. N.jugosa, G. O. Sars, Moll. reg. arct. Norv. p. 88, t. 6. f. 9, a-c. 'Lightning' Exp. St. 2, 3. 'Porcupine' Exp. 1869 : St. 23, 23a, 25, 61. And var. koreni: more or less smooth or wanting the concentric ridges, and havino* a broader rostrum. 1870: Atl. 3, 9, 12. Distribution. Finmark to Bergen coast, Bay of Biscay, Palermo, New England ; 50-552 fms. Fossil. Pliocene ; Calabria and Messina. I am now inclined to consider the recent species distinct from N.jugosa of the Coralline Crag. The fossil species is regularly tri- 1 Depressed. |