CRUSTACEA OF THE MERGUI ARCHIPELAGO. 215 



121. PoRCELLAJSTA JAPONiCA, de Haan. 



Porcellana japonica, de Haan, Fauna Japonica, Crustacea, p. 199, 

 pi. 1. fig. 5. 



Petrolisthes japonicus, Stimpson, Proc. Acad. Nat. Sci. Phil. 1858, p. 241. 



Two individuals were collected, the smaller of the two having 

 been obtained in Elpbiustone Island Bay. 



In this species the middle and posterior portion of the upper sur- 

 face of the carapace are minutely punctated, whereas its anterior 

 part and its sides are delicately lineolate. An epibranchial tooth 

 is wanting, and the lateral margins of the cephalothorax are rather 

 acute. The anterior margins of the meropodites of the somewhat 

 unequal chelipedes are unilobate at their external angles ; the 

 exterior margins of these joints, by which they articulate with the 

 carpopodites, are armed in the small specimen with a small acute 

 tooth in the middle (whicb was not described by de Haan), but 

 in the larger individual these margins are unarmed. The car- 

 popodite is quite as long as the carapace ; its anterior margin is 

 armed, in both specimens, with only one small acute tooth, 

 situated at the proximal end, and the posterior margin is bispi- 

 nose, being armed with an acute tooth at the distal end, and 

 with a second placed a little before it. The outer surface 

 of the palm is rather convex, and the fingers are shorter than 

 the palm, especially in the larger hand. They are hairy on their 

 inner margins as in the preceding species. 



Porcellana japonica is represented in the seas of New Zealand 

 by Porcellana elongata, M.-Edw., a species which may be dis- 

 tinguished from that of de Haan by the upper surface of its 

 carapace being distinctly granulated. Porcellana inermis, Has- 

 well (nee Heller), from Port Denison, will probably prove to be 

 identical with. P. elongata. 



Dimensions of the larger specimen : — 



millim. 



Length of cephalothorax 8^ 



Breadth of same 7§ 



Length of carpopodite of anterior legs 85 



Length of larger hand 15| 



Porcellana japonica has hitherto been recorded only from the 

 Japanese and Chinese Seas (de Haan, Stimpson). 



