The Atoll of Funafuti, Ellice group : its zoology, botany, ethnology and general structure based on collections made by Charles Hedley of the Australian Museum, Sydney, N.S.W.
Clathurella irretita, sp. nov. — (Fig. 43)
Clathurella irretita, sp. nov.
Shell ovate-fusiform, narrow, turretted and sharply angled below a sloping shoulder. Colour white, from the suture to the angle opaque, below the angle hyaline with opaque beads; protoconch buff yellow, a splash of the same on the anterior dorsal portion of the last whorl; a pale yellow thread, confined to one spiral cord, ascends each whorl below the angle, and another surrounds the last whorl below the periphery. Adult whorls four and a half. Sculpture—the last whorl bears fifteen longitudinal costse which cross the flattened part of the whorl obliquely, here they are separated by twice their breadth; above the angle they bend and enlarge suddenly, towards the base they curve in and vanish at the basal constriction. On the penultimate whorl these costse alternate with those below the suture. These longitudinal costæ are over-ridden by a series of fine sharp spiral cords knotted at each costa; the last whorl carrying four larger and more undulating ones above the angle and ten below it; on the base are six simple cords. Protoconch horny, mamillate, three and a half whorled, the larger sculptured with a raised network, contrasting sharply by colour and texture with the adult shell, which suddenly commences with a thick raised white tongue at the suture. Aperture narrow and elliptical, columella arched, overlaid by a callus which ends abruptly where the mouth narrows. Canal short and wide. Outer lip massive, ridged externally by a dozen transverse cords which denticulate the edges; within are seven weak entering ridges. The aperture mounts the preceding whorl to the height of two spiral cords, and encloses a deep wide anal notch with a prominent callus. Length 5, breadth 2 mm.
One specimen from the lagoon beach of Funafuti.
Closely allied to Clathurella euzonata, Hervier,* from which it differs by being narrower, sharper angled, and sculptured by finer and more numerous cords. With his species Hervier associates C. bilineata, Angas, and C bifasciatum, Pease.
* * Hervier—Journ. de Conch., xliv., 1896 (1897), p. 143ibid., xlv., 1897, p. 102, pl. ii., fig. 6.