OCR Text |
Show 1881.] THE SURVEY OF H.M.S. 'ALERT.' 29 dinally plicated, spirally ridged, and everywhere ornamented very beautifully with very numerous close raised lamellae or lines of growth. The longitudinal folds or costae are oblique, attenuated above, and rapidly widening inferiorly ; they number 9-10 on the penultimate, and about one more on the last whorl, on which, a little below the middle, they become obsolete. The spiral lirae are for the most part of about equal thickness, and vary in number from about 7 to 9 on the upper volutions, and from 16 to 20 on the last; the one at the extremity, which, as it were, forms the cauda, is twice or thrice as thick as the rest. Aperture ovate, white, together with the canal occupying rather more than half the entire length. Columella arcuate above, and of a pale greenish tint. Labrum frilled at the margin. Canal oblique, recurved, rather shorter than the aperture. Length 30 millims., diam. 12 ; aperture and canal 16 long and 6 wide. Another specimen is 26 millims. long, 11 broad; and its aperture with the canal has a length of 16 millims., and a width of 6. Operculum brownish yellow, somewhat ovate, not acute at the nuclear end. Hab. Station 6. This is a very beautiful species on account of the charming nature of the sculpture, in which respect it resembles T. crispus of Couthouy, which, however, is easily distinguished by the very different form of the whorls. The figure in Gay's work represents the costae narrower and more sharply defined than in the specimens which I identify with this species. EUTHRIA ATRATA, sp. n. (Plate IV. fig. 5.) Shell ovately fusiform, purplish black. Whorls 7-8; nuclear ones rather large, smooth ; the rest convex, with a slight depression at the upper part, longitudinally strongly ribbed and finely spirally striated. Costae narrow beneath the suture, and vanishing on the last whorl a little below the middle. Aperture less than half the shell in length, ovate, continued beneath into a short, narrowish, oblique deep canal, of the same colour as the exterior. Labrum arcuate, thickened by the last rib, with a small tubercle at the commencement of the canal. Columella covered with a thin enamel, which is whitish inferiorly, arched in the middle. Length 16 millims., diam. 7 ; aperture 7 long, 3 wide. Hab. Station 5 and Puerto Bueno, 2-7 fathoms, bottom rocky; also Boija Bay, 20 fathoms, on a stony and shelly bottom. The principal characteristic of this species is the intensity of the purplish-black colouring. Four of the specimens have furnished resting places for a small Hermit-crab. EUTHRIA MERIDIONALIS, sp. n. (Plate IV. fig. 6.) Shell fusiformly ovate, small, brown, pale at the apex. Whorls 6; apical one smooth, whitish, convex; the rest only slightly convex, longitudinally costate, and transversely sulcate. Suture scarcely oblique, rather deep. Costae a little slanting, somewhat arcuate, about 14 on the last whorl, which do not attain quite to the |