1908.] ge:j^us of amphipod Crustacea. 379 



Set(B. — The first three joints are without setae. The 4th has 

 twelve auditory set^e on the posterior margin (fig. 9), eleven i^rox- 

 imally and one at the distal angle ; anteriorly it is provided with 

 nine groups or rows of small sette set transversely on the margin, 

 with one auditory and one small seta at the distal angle. The 5th 

 joint has one auditory seta at the posterior distal angle ; and, on 

 the anterior margin, eleven of the small transverse rows of setfe,. 

 with a fringe of setae and one auditory seta at the distal angle. 



The flagellum is half as long again as the peduncle, fifiform,. 

 much more slender than that of the female. It consists of 38 

 small joints ; the first with the posterior margin shorter than the 

 anterior, and the others with the anterior angle a little produced 

 downwards, giving an oblique look to the articulations. The first 

 25, subequal in length, gi-adually decrease in width, the following 

 joints being longer and narrower. Each joint bears anteriorly a 

 little bunch of seta? at the distal angle. There is a calceolus on 

 each of the first three joints, then one on alternate joints to the- 

 35th, the calceolus (fig. 8) being set on a little protuberance above 

 the bunch of setse. The first joint also bears a large " Rheich- 

 zapfen." The three terminal joints are exceedingly slender, the 

 apical one tipped with two sette. 



In the second specimen, 21-5 mm. long, the flagellum is twice 

 the length of the peduncle and consists of 40 joints, the terminal 

 four very minute and without calceoli. The first four have each 

 a calceolus, after which they occur on alternate joints to the 36th. 

 The third specimen, 20 mm. in length, has lost the tips of both 

 antennas ; 33 joints still remaining on each. 



Oral Parts. — Upper and Loioer Lips (PI. XIY, figs. 10 & 11). 

 The upper lip is elongate, deeply hollowed, apex entire and pro- 

 duced forward. The lower lip is divided at the tip into two 

 lobes, with a minute pellucid structure between the apices. 



Mandible.— i''e«i«Ze (PI. XIV. figs. 12 & 13). The large basal 

 portion carrying the palp is produced forwards in a laminar 

 process, with truncate cutting-edge, feebly spatulate, no molar. 

 On the inner surface distally are three spinules. 



The 1st joint of the jo«Z^j is very small ; the 2nd large, about 

 six times as long as the 1st, broad, rounded anteriorly, carrying 

 along the distal half of the anterior surface inside the margin a 

 row of 25 long, curved bristles, with plain shafts and minutely 

 serrate tips. The 3rd joint is lanceolate, as long as the 2nd, 

 but only half the width, with 17 long bristles on the anterior 

 margin of the right mandible, 18 on the left mandible. These 

 bristles are plumose for half their length and curved, the distal 

 three being more widely spaced, smaller and more curved than the 

 others. At the apex of the joint, set at a different angle from 

 the others and from each other, are two bristles, the apical one 

 half the length of the other, which is the longest on the palp ; 

 the shafts are dentate on either side, and the tips are long, stift' 

 and finely plumose. The greater part of the joint is thickly 

 covered with fine transparent flat spines. 



