REPORT ON THE AMPHIPODA. 003 



Upper Antenna;. — The joints of the peduncle successively decreasing in length and 

 thickness, the first about twice as long as broad ; the flagellum three or four times as long 

 as the peduncle, rather thick near the base, the joints numbering .sixty-two, none very long, 

 most of them widening a little distally, and some widening much, namely the first, third, 

 sixth, ninth, eleventh, thirteenth, eighteenth, twenty-fourth, twenty-ninth, thirty-fifth, 

 fortieth, forty-fourth ; these carry cylinders, in groups of three or four, about as long as 

 two succeeding joints ; all the joints, except perhaps the last two, carry small calceoli, 

 many of the upper ones having the lower margin fringed with four or more ; some are 

 found at the apex of the first joint of the peduncle, and there is a row along the distal 

 half of the lower margin of the second and third joints. 



Lower Antennas. — The peduncles a little longer than in the upper antennae, the 

 flagella of about the same length ; the first joint not much inflated, the gland-cone 

 minute, not prominent ; the distal rim of the coalesced first and second joints a little 

 crenulate, with a few setae or slender spines ; the third joint more than half the length of 

 the fourth, which is rather longer than the fifth ; all three have spines on the krwer 

 margin and at the apex of the upper ; the flagellum of fifty-six joints, evenly tapering, 

 armed as in the upper antennae with small calceoli, some of the upper joints having as 

 many as six, and the third, fourth, and fifth joints of the peduncle having two or three 

 rows of them along the under (or perhaps the inner) side. 



Upper Lip not well made out, but apparently membranous in texture, with the 

 rounded distal margin strongly ciliated and slightly projecting at the centre. These 

 characters, however, must not be regarded as very definitely ascertained. 



Mandibles. — The cutting-plate narrow, with its edge divided into seven teeth, 

 none of them very large ; the secondary plate on the left mandible similar to the 

 principal one, which to a certain extent clasps it, but smaller, its edge divided into five 

 teeth ; on the right mandible this plate is as usual of slighter construction, it is curved, 

 divided apically into two slender teeth, and has a denticle on the outer convex margin ; 

 the spine-row of seven slender, denticulate, more or less curved spines ; the molar 

 tubercle prominent, the oval crown set with numerous rows of denticles ; a blunt- 

 headed process adjoins the base of the palp, just over the molar tubercle ; the first joint 

 of the palp is short, the second is broader than either the first or third, a little longer 

 than the third, concave behind, widening distally, with some small spines at intervals on 

 the front margin, and on the outer surface a couple about one-third of the length from 

 the base, and (commencing at about the centre of the same surface) a curved row of 

 sixteen, slightly curved, pectinate spines, graduated in size, those in the middle of the 

 row being the longest ; the third joint has its concave front margin crowded with 

 pectinate spines of various lengths, and two or three long ones close to the base of the 

 hind margin. 



Lower Lip. — The principal lobes much ciliated, somewhat dehiscent, distally 



