e 



1544 THE VOYAGE OF H.M.S. CHALLENGER. 



in the female wanting. Limbs of the perseon short, with wing-like projecting side-plates. 

 Both pairs of gnathopods with complex denticulate chehe and very thick wrists dilated 

 helmet-like. Large gland-cells in the first joint of the first three perseopods. Th 

 laminar first joints of the third and fourth perseopods comparatively small, triangular, 

 and pretty much alike. Fifth perseopods similarly formed, but much feebler. 

 Peduncles in the first and second pairs of uropods elongate, almost equal in length. 

 Kami of the third pair of uropods broadly lanceolate (Hossenformig verbreitert)." 



It may be observed that the epithet triangular does not very well suit the first joint 

 of the third perseopods. Bovallius in defining the genus states that the third perseopods 

 are not longer than the fourth, and that the peduncles of the first pair of uropods are 

 longer than the rami, but the characters are not applicable to all the species. 



B rachyscelus crusculum, Spence Bate (PL CXCV.). Specimen A. 



1861. Brachyscelus crusculum, Spence Bate, Ann. and Mag. Nat. Hist., ser. 3, vol. viii. p. 7, 



pi. ii. figs. 1, 2. 



1862. „ „ Spence Bate, Brit. Mus. Catal. Ampli. Crust., p. 333, pi. liii. 



figs. 2, 3. 

 1887. Thamyris crusculum, Bovallius, Systematical List of Amph. Hyper., Bihangtill K. Svensk. 



Vetensk-Akad. Handl., Bd. 11. No. 16, p. 31. 



The postero-lateral angles of the first two pleon-segments produced into small acute 

 points, simply squared in the third segment. The heart shows several constrictions, the 

 lateral orifices in the first two divisions appearing to be within the third and fourth 

 segments of the perseon. 



Eyes large, covering the sides of the head except a small strip at the back. 



Upper Antennae. — Terminal joint of the peduncle almost evanescent, first of the 

 fiagellum long, the brush on the convex side not developed in the specimen but in 

 preparation, the opposite margin carrying many filaments almost from the base to the 

 narrowly produced apex, this apex no doubt representing the second joint still in 

 coalescence with the first ; the following joint minute, abruptly narrower than the apex of 

 the first ; the termination broken. 



Lower Antenna}. — The basal joint with the gland-cone not completely coalesced with 

 the wall of the head; the following (third) joint of the peduncle long, curved, distally 

 widened, the fourth joint similar, a little longer, the fifth narrower, not longer than the 

 third ; the first joint of the fiagellum rather shorter than the last of the peduncle, much 

 curved, and in our specimen obstinately doubled upon itself; the terminal joint scarcely 

 half as long as the preceding. The joints were almost entirely smooth, though with 

 indications, especially on the last, that the usual fringe of short filaments would be 

 developed later. 



Mandibles. — The trunk very small, especially narrow where the palp is attached, 



