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



(1850), under the name of Solenocei-a philippii. Besides P. sipho- 

 nocerus the Penceus distinctus of De Haan (Faun. Japon. Crust. 

 p. 194, 1849) evidently belongs to this genus, and must be desig- 

 nated Solenocera distincta. Of it I have seen no specimens. 



Perhaps also the Penceus crassicornis of Milne-Edwards (Hist. 

 Nat. Crust, ii. p. 418, 1837) from India should be referred here. 



Peisletjs dobsoni, sp. n. (Plate XVII. fig. 2.) 



Cephalothorax smooth, not hairy or scabrous, with the cervical, 

 gastro-frontal, and cardiaco-branchial sutures faintly indicated. 

 Antennal and hepatic spines present, but no pterygostomian spine at 

 the anteroinferior angle of the cephalothorax. Rostrum slender, 

 not quite reaching to the apex of the antennal scale, 7-9-deutate 

 above, about four of the teeth being posterior to the frontal margin, 

 the posterior tooth separated by a greater interval than the others, 

 which are equidistant from one another; there are no teeth on the 

 anterior third of the upper margin, nor on the inferior margin ; the 

 apex, in the only specimen which appears perfect, is acute. Poste- 

 riorly the rostrum is prolonged into a short median dorsal crest, 

 which terminates at some distance from the posterior margin. There 

 are no longitudinal median dorsal sulci. The first five postabdomi- 

 nal segments are rounded at their postero-lateral angles ; the poste- 

 rior margins of the first, second, fourth, and fifth have a semicir- 

 cular notch on each side of the body ; there is a longitudinal median 

 dorsal carina on the third to sixth segments, which is but faintly 

 indicated on the third segment, and a faintly indicated lateral carina 

 on each side of the fifth and sixth segments ; the terminal segment 

 is longitudinally sulcate above, the extremity very slender and acu- 

 minate, the lateral margins ciliated, but without mobile spines ; the 

 appendages of the sixth segment somewhat oblong-oval, and nar- 

 rowed at the distal extremities. 



The eyes are very large ; the antennules with the joints of the pe- 

 duncle flattened on their inferior surfaces, and with two flagella, of 

 which the inner is nearly twice as long as the outer, but not as long 

 as the cephalothorax. Antennae with the flagella very long. The 

 crowns of the mandibles are slightly concave on their inner surfaces, 

 the cutting-edges thin, and with a tooth near the apex ; the palpus 

 tomentose and 2-articulate, the terminal joint foliate, triangular and 

 acute. The second maxillipedes are densely hairy ; the outer maxil- 

 lipedes are very slender, almost styliform, and their exognathi reach 

 almost to the extremity of the penultimate joint. The three ante- 

 rior pairs of legs are small and very slender, successively slightly in- 

 creasing in length, but the third pair not more robust than the pre- 

 ceding ; they are very feebly didactyle, and the fingers are much 

 shorter than the palmar portion of the hand ; the fourth pair of legs 

 are very feeble, and much shorter than the preceding ; the fifth pair 

 are obsolete, thickened, and two-jointed, the terminal joint consti- 

 tuting an indurated corneous lobe ; there is also a small lobate pro- 

 longation at base of each of the fourth legs ; and the lobe between 

 the bases of fifth pair of legs (which resembles in form that usual 



