REPORT ON THE AMPHIPODA. 777 



and spines stronger, the rudimentary outer plates are smaller ; in the second gnathopods 

 the hand is longer in proportion to its breadth, and the first joint of the limb longer in 

 proportion to the other joints ; the peduncles of the third uropods are less elongate in 

 comparison with the rami, and the long narrow telson is far less sharply pointed, or rather 

 has the narrow apex rounded. There are other points of difference which a minute 

 description of the whole animal would display. 



Lcucothoc tridcns, n. sp. (PI. XLVIL). 



The first three segments of the pleon with the postero-lateral angles scarcely acute ; 

 those of the second segment in this, as in the preceding species, perhaps having a little 

 produced point. 



Uyes between round and oval in shape, dark in the specimen preserved in spirits. 



Upper Antennse.- — The first joint not longer than the second, having a very small 

 apical tooth ; the second joint with a small spine near the middle of the upper margin, 

 and a feathered cilium or seta at the ajjex of the lower ; the third joint nearly half the 

 length of the second ; the flagellum very short, with five joints remaining, probably not 

 more than one or two missing, the first the shortest, and the minute narrow secondary 

 flagellum shorter than this. 



Lower Antennse. — Similar in proportions to those of Lexicothoe miersi; the flagellum 

 consisting of only six slender joints. 



Upper Lip narrow, very unequally bilobed, finely fringed with cilia except at the 

 apex of the longer lobe. 



Mandihles. — The cutting-plates nearly as in Leucoilioe miersi; the spines of the 

 spine-row much less numerous ; the second joint of the palp with two pairs of spines near 

 the middle of the front margin and one at its apex, the third joint a little more than half 

 the length of the second, with two spines or setse on its narrow apex. 



Lower Lip) of very thin texture, the cilia few on the rounded distal margins of the 

 principal lobes. 



First Maxillie. — Inner plates small, oval, with a very small apical seta ; the seven 

 spines on the distal margin of the outer plate similar to those in Leucotho'c miersi, the 

 lateral denticle not large on any of them, the setse at the apex of the inner margin not 

 large ; the palp as in the other species. 



Second Maxillae. — The inner plate broader than the outer, with two small spines on 

 the apex and one on the inner margin just below the apex ; the outer plate reaching a 

 little beyond the inner, with two apical spines, and a seta on the outer margin just 

 below the apex. 



Maxillipeds. — The rudimentary plate of the second joint apj^cars to be extremely 

 small; the joint has spines on the outer apex, and two on the margin below; the first 



(zooL. CHALL. EXP. — PART Lxvii. — 1887.) Xxx 98 



