GENERA UROTHOE AND UEOTHOIDES. 17 



row of ten unequal spines, and the flagellum consists of twenty-five joints. In a female 

 specimen from the same locality the fourth joint has seventeen spines in one row and 

 three in the other ; the fifth joint is decidedly shorter than the fourth, and has nine or 

 ten spines, the long setae of this and the preceding joint being fewer than in the female 

 specimen described of Urothoe brevicornis. The flagellum is as long as the last joint of 

 the peduncle, the first joint carrying two spines near the distal end, and eight long setae 

 round it ; the little terminal joint is scarcely more than a third of the breadth of the 

 preceding. 



Mandibles as in Urothoe elegans, but the long setae on the second joint of the palp 

 more numerous, and the long narrow third joint having ten spines along the front 

 margin, and two at the apex, together with four others that are long and more or 

 less setiform. 



Lower lip. Mandibular processes strongly developed. 



First maxillce. The curved inner plate with four or five setae on and near the apex ; 

 outer plate and palp as in Urothoe elegans. 



Second maxillm with plumose setae passing round the apex and the distal half of the 

 inner margin of the inner plate, which also has a row of plumose spines on the apical 

 margin, these maxillae not sensibly differing from those of Urothoe pulchella. 



Maxillipeds nearly as in Urothoe jndchella, the inner plates rather broader, the outer 

 with six stout spines and twenty setae, thus arranged — a short seta, three rather large 

 ones, a group of three small ones, of which the middle is the longest, such a group 

 followed by a stout spine occurring four times in succession, then a single seta, two 

 stout spines, and (on the apical margin) three plumose setae. The number of spines 

 and setae, however, cannot be depended on as constant in this species, or probably in 

 any of the others. Here the third joint of the palp is more elongate than in Urothoe 

 pulchella. 



First gnathopods. Side-plates narrow, with a group of three spinules at the lower 

 hind corner. The first joint slender, with a few spinules on the front margin, many 

 long pectinate setae on the hind margin, and four groups of them on the inner surface ; 

 the second joint short, with one group of setae on the hind margin; the third joint 

 with one or two setae on the hind margin, its apex acute ; the wrist almost as long as 

 the first joint and much broader, the convex hind margin or breast closely fringed with 

 unequal setiform spines, the inner surface carrying five or six groups, the row of 

 pectinate spines at the distal margin twelve in number ; overlapping this row and 

 running to the front margin is a row of microscopic spinules, such a series being found 

 in all the species examined ; the hand about three quarters as long as the wrist, much 

 narrower, with setiform spines in two rows on the inner surface, in one row on the 

 outer, and fringing more than the distal half of the hind margin ; the pahn oblique, 

 microscopically pectinate, fringed with various setules, and defined by a stout spine, 

 VOL. XIII. — PART I. No. 3. — January, 1891. d 



