304 MR. E. J. MIERS ON THE PEN^EID.E. [Mar. 5, 



anteroinferior angle, &c. The sex of the specimens of P. sculplilis 

 is not stated. 



In the P. avirostris, Dana (U.S. Expl. Exp. xiii. Crust, i. p. 603, 

 pi. xi. fig. 3, 1852), from Singapore, which is but shortly charac- 

 terized, the rostrum is somewhat of the same form, but straighter, 

 shorter, and only 6-toothed above, the legs of the two posterior pairs 

 much more slender than the preceding (sex not stated). The 

 cephalothorax is not dorsally carinate in its posterior half. 



Pen.eus affinis. 



Penceus affinis, M.-Edw. Hist. Nat. Crust, ii. p. 416 (1837); 

 De Haan, Faun. Japon. Crust, p. 192, pi. xlvi. fig. 3, P. barbatus 

 (1849). 



Penaus velutinus, Dana, U.S. Expl. Exp. xiii. Crust, i. p. 604, 

 pi. xl. fig. 4 (1852). 



Whether this species be the P. affinis of Milne-Edwards must remain 

 uncertain, as his type specimen has not been figured, and his short 

 description leaves many particulars unnoticed ; but it is certainly the 

 one figured by De Haan under the name of P. barbatus, and referred 

 by him in the text to P. affinis. P. velutinus of Dana (U.S. Expl. 

 Exp. xiii. Crust, i. p. 604, pi. xl. fig. 4, 1852) from Lahaina, Sand- 

 wich Islands, seems to be also referable to the same species. His 

 description applies to it ; and although his figure, when compared with 

 that of De Haan, presents some slight differences, they are probably 

 due to inaccuracies of drawing. Examples of this species are in the 

 British-Museum collection from Japan, Sandy Cape, Sharks' Bay, 

 West Australia, and the Gulf of Suez ; hence it would appear to 

 have a wide geographical range. 



P. constrictus, Stimpson (Ann. Lye. Nat. nist. New York, x. 

 nos. 4, 5, p. 135, 1871), from the coast of Carolina, U. S., of which 

 there is one specimen in the British-Museum collection, presented 

 by the Smithsonian Institution, is nearly allied to the above. The 

 teeth of the rostrum are stated to be equidistant by Stimpson ; but in 

 the specimen I have examined, the last tooth is (as in P. affinis) 

 separated by a wider interval than the preceding. It differs, how- 

 ever, in being much less pubescent (the postabdomen is naked and 

 glossy), and in having a very deep longitudinal median sulcus on the 

 last segment, which is margined by lateral carinse. 



P. pubescens of the same author (L c. p. 133), based upon a single 

 female example with imperfect rostrum from St. Thomas, would also 

 seem from the description to be closely allied to P. affinis, and, in 

 the absence of specimens for comparison, I am unable to say how it 

 may be separated from that species. It will probably prove to be 

 distinct, on account of the widely distant locality ; therefore I do not 

 quote it as a synonym of the Indo-Pacific form. 



Penceus stylifertjs. 



Penceus styliferus, M.-Edw. Hist. Nat. Crust, ii. p. 418 (1837). 



There is a single specimen, a male, in bad condition, which I refer 



