OCR Text |
Show 1881.] THE SURVEY OF H.M.S. 'ALERT.' 35 TECTURA (PILIDIUM) COPPINGERI, sp. n. (Plate IV. figs. 12, 12a.) Shell cap-shaped, thin, sculptured with numerous fine, thread-like, granulous lirse radiating from the apex to the margin, and with fine concentric lines of growth. The colour is dirty white, varied with two or three bands of a pale slate-colour which encircle the shell at irregular intervals, and are interrupted by the radiating lirse, which are white. This feature is more apparent within the shell, where the surface is very smooth and shining. Margin nearly simple, very faintly crenulated by the extremities of the ridges, roundly ovate in form. Apex rather acute, not greatly curved down, and very near the anterior end. Length 5£ millims., diam. 4£, height 2|. Hab. Station 7. This is the southern representative of the northern Tectura {Pilidium) fulva of Midler. It is rather more circular than the latter ; and the colour of the single specimen at hand is different. CHITON BOWENII, King. Hab. Cockle Cove, 2-32 fathoms., m u d bottom. CHITON (CALLOCHITON) ILLUMINATUS, Gray. Hab. Station 6. CHITON (PLAXIPHORA) CARMICHAELIS, Gray. Hab. Stations 3 and 6. CHITON (TONICIA) FASTIGIATUS, Gray. Hab. Tom Bay, on the shore. CHITON (ISCHNOCHITON) IMITATOR, sp. n. (Plate IV. figs. 13-13e.) Shell elongate ovate, moderately elevated, subangularly arched at the middle, dirty white. Valves narrow, with a single notch on each side, exhibiting small slightly raised lateral areas, which towards the margin have a few transverse strong grooves or marks of growth. Front margin sloping very slightly on each side from the middle in a posterior direction; hind margin straight. Sculpture consisting of close flat granulation, exhibiting a somewhat serial arrangement. Laminae of insertion very thin, with a wide sinus between them. Anterior valve sculptured like the others, with fourteen fissures within, the thirteen teeth between them being sharp and straight-edged. Posterior valve with a central mucro, from which there is a faint ridge on each side to the lateral extremity, also marked with concentric lines of growth at intervals, and with the inner marginal fissures twelve in number. Scales of the mantle minute, imbricating, ovate, arranged lengthways; under the microscope they appear very coarsely transversely grooved. Length 11 millims., diam. of fourth valve 5. Hab. T o m Bay, on the shore. This species is very like the northern C. albus; and C. viridulus of 3* |