REPORT ON THE AMPHIPODA. 1445 



gnathopods equal in length, and the postero-lateral angles of the first three pleon- 

 segments rounded ; he neither mentions nor figures the dorsal tooth of the seventh 

 perason-segment and the first two pleon-segments, and the telson, as he figures it, can 

 scarcely be considered triangular ; but the more striking peculiarities of his new species 

 probably diverted his attention from features less notable, which in this genus happen 

 to be very difficult to make out ; that he divides the sixth joint of the fifth perseopods 

 into two in the figure is obviously due to some accident. 



In the young, less than one-twentieth of an inch long, the shape is not more slender 

 than in the parent, none of the segments are dorsally produced ; the upper antenna? 

 appear to consist of one thick joint, longer than thick, and a terminal short joint ; in 

 the gnathopods the fingers have a greater proportionate length than in the adult ; 

 the first and second perseopods have the fourth joint distally dilated, the front margin 

 being produced into a pointed apex, within which lies a somewhat curved spine as 

 long as the apical process, and having the side pectinate which faces the fifth joint ; 

 the long third peraeopod has a broad fourth joint with the front margin smooth, ending 

 in a small apical tooth, within which is planted a spine that projects beyond it ; the 

 much narrower fourth joint of the fourth peraaopods is similarly armed ; the fifth 

 perseopods are feeble as in the adult ; the rami of the pleopods, as usual at this stage of 

 development, have only two joints, a long and a short one, the long one having a cleft 

 spine at the upper part. 



Primno latreittei, n. sp. (PL CLXXIX., A.). 



The general outline not differing materially from that of Primno macropa ; the last 

 segment of the perajon is dorsally pointed behind but not strongly produced. 



The Upper Antennas (in the male) have the first joint of the peduncle as broad as 

 long, the second very short, the third inconspicuous or absent, the flagellum of the 

 specimen figured, consisting of one joint, slightly bent, proximally tumid, the tumid 

 part having a small group of five short filaments at the distal end ; the remainder of 

 the joint tapering, crossed by numerous lines indicating the future joints. In fig. ct.s.C, 

 from another specimen, the second joint of the peduncle is more distinct, the flagellum 

 with the tumid part forming the first joint, the remainder tapering, indistinctly divided into 

 about eighteen small joints. In the female these antenna? are nearly as in Primno guerini. 



TJie Lower Antennae are shorter and thinner than the upper, the three free joints 

 uf the peduncle short, not longer than broad ; the flagellum in the specimen figured 

 consisting of one joint, long, curved, narrowing in the distal half, but not to a sharp 

 point ; the internal appearance in these as in the upper antenna? indicated a future 

 resolution into numerous joints, and perhaps the surface is marked with rings as 

 in the upper pair, but on the glassy skin this could not be made out with certainty. 



