I CETJSIACEA. 297 



peduncles of the antennae are very short, completely concealed 

 beneath, the large basal scales, which reach slightly beyond the an- 

 tennal peduncles, narrow to their apices, and have a small spinule 

 at the distal ends of their outer margins. The outer maxiUipedes 

 are rather robust and elongated, reaching, when thrown forward, 

 almost to the apices of the antennal scales. The first legs are much 

 shorter than the following, with the joints compressed, the dactyli 

 acute, and the basus and ischium-joints have each a small spine at 

 the distal ends of their inner margins ; the second and third cheli- 

 pedes are slender (the basus-joint of the second legs bears a small 

 spine) ; the third are longer than the second ; the fourth legs are 

 slender and rarely as long as the third ; the fifth are imperfect. 

 The rami of the uropoda are narrow, and reach about to the end of 

 the terminal segment ; the outer has the lateral margins nearly 

 parallel ; in the inner ramus they converge very slightly to the 

 rounded extremity. Colour (in spirit) purplish beneath "the cinereous 

 pubescence. Length about 2 inches 10 lines (72 millim.). 



The unique example (a female) was obtained at Albany Island in 

 3-4 fms. 



The palpi of the mandibles are two-jointed ; the joints flattened, 

 dilated, and ciliated, as in Penceus. 



As the specimen is unique, I have not been able to make a com- 

 plete examination of the branchiee ; but I think (as in the true 

 Pencd as restricted by Mr. Spence Bate) no true podobranchise are 

 present, but merely the epipoditic appendages or " mastibranchise " 

 as he denominates them *. 



There are, besides, in the collection from Port Denison a speci- 

 men closely allied to Pasiphcea and to Leptochela, Stimpson ; and 

 another crustacean, perhaps belonging to the Penseidea, which, being 

 in very mutilated condition, cannot be described in detail, and 

 which I leave for the present undetermined. 



• Vide Spence Bate " On the Penseidea," Ann. & Mag. Nat. Hist. ser. 5, viii. 

 p. 174 (1881). 



In tnis recent memoir on the Penseidea several new genera and not a 

 few new species hare been very briefly characterized, to none of which, I 

 believe, can our new form be referred. The descriptions, however, are in- 

 sufficient. From Hemipenisus, which this species resembles in its short and few- 

 toothed rostrum, it differs in the structure of the flagella of the antennules. 



Mr. Spence Bate includes in the very insufficiently defined genus Peneeopsis the 

 P.stylifirus, M.-Edwards, vrith which he apparently considers P. doisowi, Miers, 

 to be identical. He has strangely overlooked an important distinction, twice 

 mentioned by me in my paper {vide Proo. Zool. Soo. 1878, pp. 305, 307), 

 namely the absence of lateral marginal spinules on the terminal postabdominal 

 segment. They are absent, I may add, alike in the female and in Prof. 

 Wood-Mason's small male. The existence of these in P. styliferus is mentioned 

 by Milne-Edwards in his original description of that species, and they are 

 present also in a specimen referred to P. styliferm in the British-Museum 

 collection. 



