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Show 1900.] POLYNOID EROM NEW ZEALAND. 975 recognized its proper genus ; in preference to the specific name conferred by Quatrefages, who had most unaccountably referred it to Aphrodita. The most striking and interesting feature about the Annelid is the very definite, subelytral groove along the back (Plate L X . fig. 3) with the row of tubercles for the support of the overlapping moieties of the elytra, so that the groove is constantly open for the respiratory current. I am not aware that anything so definite has been hitherto noted in any Polynoid, and I suggest the term " respiratory channel " for it. The definite " exhalant aperture," too, formed by the emargina-tions of the last pair of elytra (Plate L X . fig. 1) complete the utility of this channel. The presence of such an aperture formed in this way is mentioned and figured by Huxley for L. squamatus, in his * Manual of Anatomy of the Invertebrates,' 1877, p. 228. The peculiar hair-like character of the neuropodial bristles-suggesting the felted hairs of Aphrodita-are also a peculiarity of the species, especially in their number and softness of texture. DESCRIPTION OF THE SPECIES. By W. MALCOLM THOMSON. General appearance.-The specimens measured in a preserved condition ranged in length from 80 m m . downwards and in breadth from 35 m m . Average specimens were about 68 m m . long by 25 m m . broad. In shape the animal is a very regular oval, the anterior end being rather narrower than the posterior. The upper surface of the body is strongly convex, both in the longitudinal and transverse planes, tbe ventral surface being flat or even inclined to be convex, but with the usual median groove. The dorsum is completely covered by the large imbricate elytra, of which there are twelve pairs (Plate L X . fig. 1). Between the first pair a small median notch allows the protrusion of the palps and tentacles. There is a smooth tract over the mesial moiety of the series of the elytra, bounded on each side by a row of oblong transverse ridges representing the areolae or areas of attachment of the elytra (Plate LX. fig. l,a). The median moiety of each elytron constituting this tract is coloured a warm brown, and this colour is continued outwards behind the areola (Plate L X . fig. 1, c), the anterior surface of which is coloured light buff and is smoother than the general surface. The median tract ceases at the last pair of elytra, the inner margin of each of which is notched, so as to produce a small oval aperture with distinct, upturned lips: this aperture is the exhalant respiratory pore, to which we shall return. The posterior and lateral surfaces of an elytron are beset with numerous spiny processes and also with fine hairs. Tbe margin of the body, as seen from above, is formed by a fringe of hairs constituted by the successive bundles of notopodial bristles. These hair-like bristles and the processes of the elytra collect a considerable amount of mud and afford a foothold for foreign organisms, which no doubt aid in the concealment of the animal. |
