1030 THE VOYAGE OF H.M.S. CHALLENGEE. 



produced upwards, with the adjoining part of the lower margin cut into four or five 

 serrations ; the sixth segment very small. 



Eyes lartre, oval, placed close to the lateral lobes of the head, the ocelli small, about 

 sixty-six in number, the crystalline cones not longer than broad. 



Upper Antennw much longer than the lower, first joint long and slender, but thicker 

 and a little shorter than the second joint, with three spines along the lower margin ; 

 second joint carrying a few groups of slender setae ; third joint less than one-third the 

 leno-th of the second, only a little longer, or not longer, than the first joint of the 

 flagellum ; the broken flagellum contained seventeen joints, of which the first was 

 the longest ; the secondary flagellum of two slender joints, together a little longer than 

 the first of the primary. 



Lower Antennse slender, the peduncles and flagella respectively shorter and thinner 

 than those of the upper antennae ; first joint little expanded, gland-cone decurrent, 

 produced quite to the distal end of the third joint ; fourth joint longer and thicker than 

 the fifth, shorter than the first of the upper antennae ; fifth joint long and slender, 

 furnished like the fourth with some groups of slender setae ; flagellum much shorter than 

 the peduncle, of ten joints, furnished with setae, the first joint the longest, the last 

 minute. 



Upper Lip deeper than broad, with the distal margin rounded, but not broadly, 

 closely ciliated. 



Mandibles. — Cutting plate divided into eight or nine teeth ; the secondary plate 

 on the left mandible distally broad, divided into six teeth ; on the right mandible the 

 secondary plate is slighter, distally bifid, the front tooth the longer, having three teeth 

 along the front side and a little outward-pointing process above them ; spine-row on 

 the left mandible consisting of four, on the right of three, curved denticulate spines ; 

 molar tubercle with a strongly denticulate crown and a plumose seta ; the process near 

 the base of the palp prominent ; j)alp very slender, not so long as the body of the 

 mandible, set just over the molar tubercle, the first joint as long as the third, and 

 double or more than double the length of the second; the second very short, narrower 

 than the first, a little broader than the third ; the third narrow, slightly tapering, 

 tipped with two long setae, or setiform spines. 



Lower Lip. — The principal lobes deep, a little narrowed distally, very slightly 

 dehiscent, with many cflia, including a pair on each lobe that are spiniform ; the 

 inner lobes deep and narrow, much ciliated on the distal and inner margins ; mandi- 

 bular processes long, narrow, rather divergent. 



First Maxillse. — Inner plate small, ovate, tipped with two plumose setae ; outer 

 plate with seven spines on the truncate oblique distal margin, the denticles minute on 

 the slender innermost spine, prominent on the next three but only two or three in 

 number, while on each of the three outermost spines there is not more than a single 



