XIV.—On a New Species of Sclerocheilus, with a Revision of the Genus

Abstract

The Polychæte family Scalibregmidæ comprises seven genera, the limits and interrelationships of which are, however, still imperfectly known. The present paper results from a detailed study of one of these genera, a new species of which is described, chiefly from a specimen collected in Scotia Bay, South Orkneys, and entrusted to me for examination by Dr W. S. Bruce.Description of the Specimen Collected in Scotia Bay, South Orkneys.: This specimen, the only Scalibregmid found by the Scottish National Antarctic Expedition, was dredged on a stony bottom in ten fathoms at Station 325, in Scotia Bay, South Orkneys (lat. 60° 43′ 42″ S.; long. 44° 38′ 33″ W.), in August 1903.The worm, which is yellowish brown in colour (in alcohol), is 19 mm. long. The anterior portion is broad; the maximum breadth, 3 mm., is reached about the level of the 10th segment; from this region the worm tapers gradually to the anal segment. The dorsal surface of the worm is strongly convex; the ventral surface is flattened, and there is a well-marked depression which extends along the mid-ventral line from the 2nd chætiferous segment almost to the anus.