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Show 932 DR. GWYN JEFFREYS ON THE MOLLUSCA OF THE [Nov. 29, 2. PECCHIOLIA SUBQUADRATA ', Jeffreys. (Plate LXX. fig. 3.) S H E L L forming a short oblong, or squarish, very convex, thin, semitransparent, and glossy; sculpture, numerous but irregular microscopic tubercles, which penetrate the outer layer of the shell ; these are larger in front and on each side : colour pale yellowish-white : margins short and rounded on the anterior side, broad and gently curved in front, rounded but somewhat truncated on the posterior side, nearly straight at the back : Beaks small, blunt, and slightly incurved ; umbones prominent : lunule short and deep : hinge-line obtuse-angled : hinge-plate rather thick, considering the texture of the shell: cartilage long, pale yellowish : teeth none: inside polished: scars inconspicuous. L. 0*1, B. 0*15. 'Porcupine' Exp. 1869 : St. 47. 1870: Atl. 16, 17. Differs from the young of P. aByssicola in shape and sculpture. 3. PECCHIOLIA INSCULPTA2, Jeffreys. (Plate LXX. fig. 4.) S H E L L globular, with a square outline, equivalve, very thin, pearly, semitransparent, and glossy: sculpture, about 25 delicate riblets or strise, which radiate from the beak in each valve, besides microscopic and numerous concentric strise in the interstices of the riblets, and irregular lines of growth; the anterior end is smooth: colour white : epidermis membranous, sometimes partially incrusted with mud: margins bluntly angular on the anterior side, nearly straight in front, obliquely sloping or truncated on the posterior side, nearly straight at the back : beaks sunken, small, incurved ; umbones prominent : lunule heart-shaped : ossicle white, solid, obliquely twisted, unequally forked on the broader end towards the posterior side: hinge-plate short, thickened : inside glossy : scars slight. L. 0*25, B. 0*25. 'Porcupine' Exp. 1869: St. 1, 10, 22. 1870: Med. Off Jijeli (a larger valve). Distribution. Bay of Biscay ('Travailleur' Exp.); 552-645 fms. Palermo (Monterosalo) ; 162 fms. Fossil. Pliocene : Messina (Seguenza, as Verticordia ccostata, aud afterwards V. insculpta). 4. PECCHIOLIA SINUOSA 3, Jeffreys. (Plate LXX. fig. 5.) S H E L L of an irregular shape, but somewhat triangular and sinuous*, convex, thin, opaque and lustreless : sculpture, close-set microscopic tubercles arranged in longitudinal rows; they are easily rubbed off, and then the surface becomes quite smooth and glossy: colour white : epidermis filmy : margins imperfect, but rounded on the anterior side, apparently sloping obliquely in front, nearly straight at the back : Beaks very small, incurved : lunule excavated, enclosed by a slight ridge: hinge-plate narrow, twisted, and presenting the appearance of having a short notch or fold under the beak : inside nacreous : scars indistinct. L. 0'3, B. 0*35. 'Porcupine' Exp. 1870 : Atl. St. 16 (fragments only). 1 Squarisb. 2 Engraved. 3 Full of folds, sinuous. |