300 MR. E. J. MIERS ON THE PEN^ElDiE. [Mar. 5, 



P. semisulcatus, there is a short dorsal carina which does not reach 

 to the posterior margin of the cephalothorax and is not canaliculated 

 above, and the gastro-hepatic sulcus is very deep and strongly de- 

 fined. For this latter form I propose to retain Fabricius's name of 

 P. monodon, if the two species be distinct ; as it would seem that 

 the common Indian form must be designated by De Haan's name of 

 P. semisulcatus, it having been first distinctly characterized by him, 

 while it is impossible to ascertain from Fabricius's brief description 

 which of the two species was known to that author. 



The figure of P. tahitensis of Heller (Reise der Novara, Crust, 

 p. 121, pi. xi. fig. 2, 1865) resembles this species ; and iu it the ros- 

 trum is represented as 3-toothed below ; but it is described as eden- 

 tate ; so I cannot refer it with certainty to P. setnisulcatus. 



The P. carinatus of Dana (U.S. Expl. Exp. xiii., Crust, i. p. 602, 

 pi. xl. fig. 2, 1852), from Singapore, is only briefly described, but 

 appears to be identical with P. semisulcatus, with which it agrees in 

 the form and number of the teeth on the rostrum. It is not, how- 

 ever, mentioned in the description whether the longitudinal carina 

 on the cephalothorax is sulcate or not. 



Pen^eus hardwickii, sp. n. (Plate XVII. fig. 1.) 



The cephalothorax is very minutely granulated ; the cervical 

 suture is in its posterior half, aud the cardiaco-branchial altogether, 

 obsolete; a canaliculated dorsal crest extends from the base of the 

 rostrum to the posterior margin. The rostrum reaches beyond the 

 peduncles of the antennules, is 8-9-dentate above, the last tooth 

 separated by twice the ordinary distance from the preceding ; the 

 inferior margin is entire ; it is curved regularly upward toward the 

 distal extremity, which is acute. There is a spine on the underside 

 of the second joint of the first and second pairs of legs, and none on 

 the third pair. The form of the sternum is as in the P. curviros- 

 tris of Stimpson ; and the third to sixth postabdominal segments are 

 carinate as in that species. The last postabdominal segment is 

 deeply longitudinally sulcate above, and, as in P. semisulcatus, acute 

 at apex, without lateral spines. 



Hab. Indiau Seas 1 (Hardwicke). 



There are two specimens in the British-Museum collection, of 

 which the exact locality is not known. This species is most nearly 

 allied to P. curvirostris, Stimpson, from Simoda, Japan, but differs 

 in having a canaliculated dorsal crest, and a longer rostrum, which 

 is acute at the extremity ; the sutures of the cephalothorax are also 

 much less distinct. From the P. semisulcatus of De Haan, which 

 resembles this species in having a single longitudinal dorsal sulcus, 

 it differs in the form of the rostrum, which is edentate below, and 

 in having only a single spine at the base of the first pair of legs, — 

 and from the P. sculptilis of Heller, from Java, another unisul- 

 cate species, in the longer, more curved rostrum, aud in the post- 

 abdomen being keeled only on the third to sixth segments, whereas 

 in P. sculptilis all the postabdominal segments are said to be 

 keeled. 



