REPORT ON THE AMPHIPODA. 909 



rostrum, distally produced into a short tooth below ; second joint thinner, a little 

 longer; third joint about one-fourth the length of the second, distally a little widened, 

 and showing a little tubercle which seems to be the rudiment of a secondary flagellum ; 

 the principal flagellum of forty joints, which widen a little distally, and are furnished with 

 short setules, and almost every one with a cylinder shorter than the joint. 



Lower Antenna: — First three joints very short, the first with a small produced point 

 below, the second distally angled below the gland-cone, the third equal in length to 

 the first two united ; the fourth much longer than the first three united, longer than 

 the second joint of the upper antenna? ; the fifth joint longer than the fourth, like it 

 carinate and carrying numerous groups of slender spines ; flagellum of thirty-five joints, 

 not distally dilated, but besides having two or three groups of setules, carrying either 

 successively or alternately (the last six excepted) a short stout spine with a bent tip. 

 Upper Lip with the apex furred, not very broadly rounded. 



Mandibles. — Cutting plate divided into three or four small, followed by three large 

 teeth ; those represented in the Plate are worn and rounded ; the new teeth as seen in 

 preparation for the change of skin are much more sharp and distinct ; the secondary 

 plate on the left mandible divided into four teeth, of which the lowest is the 

 most prominent ; the secondary plate on the right mandible is bifid, each division 

 showing a slender apical tooth, attended by three denticles ; the spine-row of seven 

 denticulate spines ; the molar tubercle moderately prominent, with a large crown 

 occupied by many rows of denticles, the plumose seta conspicuous ; the slender palp set 

 just over the molar tubercle, its first joint distally dilated, the second straight or nearly 

 so, with four or five small setae or spines on the inner margin, the third joint longer than 

 the second, with the hind margin slightly convex, carrying at the top of the oblique apex 

 a pectinate spine longer than the joint, two others shorter, and two more much shorter, 

 and on the inner margin tw T o small spines, one at the centre, the other near the apex. 



Lower Li}). — Principal lobes broad, very slightly dehiscent ; mandibular processes 

 narrow, divergent. 



First Maxilla?. — Inner plate small, oval, with six plumose setae on the distal margin ; 

 the outer plate with eleven variously denticulate spines on the truncate margin, the 

 denticulation near the apex, the two innermost spines shorter than the rest ; of these 

 eleven nine only are shown in the enlargement of fig. mx.l.; first joint of the palp 

 with a spine on the outer margin, the second joint reaching much beyond the outer 

 plate, dilated distally, carrying on the distal margin six or seven pectinate spine-teeth, 

 shorter on one maxdla than the other, in accordance with Boeck's character for the 

 subfamily Atylinse, that the palp of the first maxilla? is two-jointed, in apice maxillse 

 sinistra} dentibus, in apice maxillse dextrse spinis armato; there are also some slender 

 submarginal spines. On the outer margin of the trunk below the palp some unequal 

 slender spines are present. 



