132 DK. C. CHILTON ON THE 



The first pleopoda of the male are shown in fig. 3, pip} 6 ; the male organ is single, 

 broader in basal half, end with small notch ; endopodite long, broad at base, apex curving 

 a little outwards, exopodite small and oval. The endopodite of the second pleopod 

 2-jointed, the second forming a very long, acute process. The other pleopoda present 

 no special features. None of them possess air-cavities so far as I can make out. 



2. AcT^ciA OPiHENSis, sp. nov. (PI. 15. fig. i & PI. 16. fig. 1.) 



Specific description. — Body very convex, rather narrow, more than twice as long as 

 broad. Surface fairly smooth, but with nurnerous scattered short setoe, especially on the 

 metasome and on the margins of the mesosome. Cejihalon with the front broad, straight, 

 with a slio'htlv-raised transverse ridcre. Posterior margins of segments of mesosome 

 nearly straight, those of the last two a little produced backwards at the lateral angles ; 

 inferior margin of fii-st segment thickened. Metasome convex; side portions of third 

 to fifth segments large and recurved ; terminal segment short, much broader than long, 

 its posterior mai'gin regularly convex. Eyes of moderate size, round. Antennae very 

 setose ; second joint of peduncle longer than the third and nearly equal to the fourth, 

 fifth about as long as fourth; flagellum as long as the second joint, of four joints, the 

 first longest, second and third subequal, fourth very small. Legs setose, scarcely 

 increfising in length posteriorly ; dactylar seta large and well-marked, simple, its distal 

 two-thirds thickened and apparently resembling a narrow circular brush. Uropoda with 

 basal joint very large, extending beyond terminal joint, exj)anded and plate-like laterally; 

 outer margm subcrenate and bearing four or five stout seta? ; outer branch small, conical, 

 scarcely projecting, tipped with a few small seta3 and one or two longer ones ; inner 

 branch reacliing a little beyond end of terminal segment, scabrous, and ending in two 

 long setae. 



Colovr yellowish, with numerous black stellate markings, some specimens nearly 

 black. 



Size. — Length about 6 mm. 



Habitat. — Timaru, luider seaweed at hiiih-Avater mark. 



Bemarks. — I have placed this species under Actcccia with considerable hesitation, for 

 it dilfers from the preceding species very markedly in the structure of the eyes. In ex- 

 ternal appearance it is rather like Tylos, but the mouth-parts are of course very different 

 and are in fairly close general agreement with those of Actcecia euehroa. The terminal 

 portion of the maxillipede is less lobed, and the masticatory lobe has a small terminal 

 lash very like that in some species of Trichoniscus. 



The pleopoda in the female are of usual form and apparently all similar ; in each the 

 exopodite is slightly larger than the endopodite and overlaps about half the succeeding 

 one. In the male the first pleopoda are rather short and very strong, the endopodites in 

 close apposition and apparently coalesced along the median line, the ends curving 

 outwards ; the second pleopod with basal portion of endopodite long, end joint not very 

 acute. 



