194 Transactions. — Zoology. 



long, found near New Zealand, to his Idotea aryentea, wliicli 

 Miers considers synonymous with I. vietalUca, Bosc. 



A specimen undoubtedly belonging to this species was in the 

 collection of Mr. E. Helms, which I examined in 1888. His 

 specimen was certainly taken on the New Zealand coast, pro- 

 bably from Picton, Marlborough. 



Idotea margaritacea, Dana, is considered hy Miers as pro- 

 bably not distinct from I. metalUca, though Dana "describes 

 the front as three-toothed, the three teeth very low, one occu- 

 pying either angle, and the third, which is less distinct, the 

 middle of the front ; the outer arc subacute and the spaces 

 between low-concave ; the body is not quite as much nar- 

 rowed behind, and the fiagellum of the outer antenna^ has 

 but four or five joints." 



It was captured between Australia and southern New 

 Zealand, 500 miles from Port Jackson, so that it belongs to 

 Australia rather than to New Zealand. It is introduced into 

 the Australian catalogue by Haswell in his " Eevision of tlie 

 Australian Isopoda . ' ' '■'■ 



Idotea lacustris. 

 Idotea lacustris, Thomson, " Trans. N.Z. Inst.," xi., p. 250 

 a879) ; ? Miers, "Jour. Linn. Soc. Zoology," xvi., p. 39, pi. i., 

 figs. 11 and 12 (1881); Thomson and Chilton, "Trans. N.Z. 

 Inst.," xviii., p. 156. 



Body narrow elliptical, fairly convex, surface finely punc- 

 tured. Head with front emarginate, antero-lateral lobes not 

 very prominent, impressed line near posterior margin of the 

 head distinctly inarked. First thoracic segment slightly 

 longer than the succeeding, with the antero-lateral angles 

 produced into rounded lobes, those of other segments not 

 produced ; succeeding segments subequal in length. Post- 

 abdomen not very convex, as long as the five preceding seg- 

 ments of thorax, composed of two short segments followed by 

 a third bearing two sutures on each side, the posterior suture 

 extending further to the centre than the anterior ; end bluntly 

 rounded, margin quite entire. Eyes rather large. Antennules 

 reaching nearly to the end of the third joint of the peduncle 

 of the antenniE, consisting of four joints, the first broad, the 

 other three subequal in length but much narrower. An- 

 tennae when retracted reaching to the posterior margin of the 

 second segment of the thorax, about one-third the length of 

 the body ; flagellum as long as peduncle, bearing, in the male, 

 a dense fringe of very short fine setae. Epimera nearly rect- 

 angular, those of second to fourth segments reaching quite 

 back to the postero-lateral angles of the segments, those of 



* " Proc. Linn. Soc. N.S.W.," vol. ix., pt. 4. 



