Page:Transactions NZ Institute Volume 15.djvu/98

Anthura affinis, sp. nov. Plate I., fig 4.

Segments of pereion subequal, cylindrical. Head somewhat shorter than the first segment of pereion. Antennæ short, not quite so long as the head; upper much smaller than the lower, consisting of four joints, of which the basal one is the largest, and a very small fifth joint bearing a small pencil of setæ; lower antennæ thick and strong, basal joint large, broad, with a groove above in which the upper antenna rests, the inner edge of this basal joint is straight and in close contact with that of the antenna on other side, along the median line; basal joint followed by three subequal joints, and a short, thick, rudimentary flagellum, the joints of which bear setæ thickly set on one side.

First pair of legs very strong, not reaching beyond the head; basos very thick distally, ischios also thick and strong, meros short, carpus subtriangular, produced along the side of the propodos, and bearing setæ on its distal extremity; propodos thick, ovate, in contact with both meros and carpus, palm short with a strong projection against which the dactylos impinges; dactylos short, strong, and curved. Remaining legs all similar, not subchelate, propodos longer than the carpus and meros together. First five segments of the pleon united so closely that the lines of suture cannot be distinguished, sixth segment distinct bearing biramous appendages; outer ramus of a single joint, half as long as the inner, semicylindrical surrounding the inner ramus, its upper inner edge serrate and fringed with long setæ very delicately plumose; inner ramus of two joints equal in length and breadth, broad, edges fringed with long setæ; telson broad, round at end, with several long setæ near the centre.

Colour—pale yellow with blotches of black on the head, segments of pereion, pleon and telson. Length about ⅓ of an inch.

Hab. Lyttelton Harbour. Found on seaweed at low tide.

This species is a true Anthura, coming apparently near to A. gracilis, from which however it is sufficiently distinct.

The first pair of legs only are chelate, all the rest are simple; they have the dactylos large and strong, the end forming a claw distinct from the basal portion; at the base of this claw three or four simple setæ arise laterally, and a short stout one on the inside. There is also a short stout seta on the inner distal angle of the propodos (pl. I., fig. 4c and d).

The pleopoda are of the usual form, having a short basal joint bearing two equal oval plates with the distal margins setose. Each of these branchial plates is slightly constricted on each side, half way between the two