REPORT ON THE AMPHIPODA. 657 



numerous rows on the inner or under side, second joint with three terminal spines, one 

 slight, another longer with an accessory thread, third very long, sharply pointed, the 

 remaining joints small, with distal rows of small cilia, the joints becoming longer and 

 more slender towards the end of the flagellum ; secondary flagellum slender, scarcely 

 exceeding in length the first joint of the primary, its first joint far the longest of the five 

 which compose it ; some small cilia and filamentary cylinders at the apices of the three 

 terminal joints. 



Loioer Antenna. — First, second and third joints very short, closely united ; first 



rather prominently lobed, cone of second prominent, blunt, third triangular ; fourth 



joint the longest, a little dilated proximally ; fifth joint shorter and much thinner ; 



flagellum of seventy-five articulations, becoming longer and very slender throughout the 



distal portion of the antennse; like the last two joints of the peduncle they are slightly 



ciliated. As in Onesimoides and Etirytenes, the base of the antenna is uncovered. 



Upper Li2) with front edge a little in advance of that of the epistome, apex furred. 



Mandibles. — Cutting edge smoothly convex, with a small tooth above and another 



below, which on the right mandible is so little prominent as to form rather a notch 



than a tooth ; secondary plate on the left mandible small, distally widened, with 



dentate edge of six teeth ; spine-row of five or six setae ; molar tubercle prominent, 



crown with numerous rows of denticles ; palp very large, set just above the articular 



condyle that rises over the molar tubercle ; first joint small, second of great size, central 



part protruding where the muscles from the first joint end, the muscles which run to the 



third joint being inserted very near the first joint and therefore overlapping the others ; 



near the distal end of the second joint there is a close-set row of pectinate spines witli 



curved tips, twelve in number ; third joint powerful, subequal in length to the second, 



ciliated on the surface, spine-border nearly straight, having some thirty-five spines 



pectinate on two edges, and at its curved apex two setules ; the opposite convex border 



naked ; the pectination of the spines seems to take a new departure at about one-third of 



their length from the base, giving the spines a jointed or geniculate appearance. 



Loiver Lip ciliated round the edges of the front lobes, the cilia on the apex and inner 

 border being stouter than the others. 



First Maxillse. — Inner plate bordered distally with seven plumose setae ; outer plate 

 much ciliated, apical border with its eleven spines in two rows, one set slender, 

 flexuous, multidentate, the other set straight, stouter, with fewer teeth ; palp with 

 second joint very broad, six spine-teeth on the apical margin minutely serrate on their 

 outer edges, a row of cilia near the spines, a long plumose one and a longer smooth one at 

 the outer corner. 



Second Maxillx. — Inner plate broader than outer, and much broader at base than 

 apex. Plates subequal in length, much ciliated on the surface and edges ; inner plate with 

 seven plumose setse along the inner margin, and a double row of pectinate spines about 



(ZOOL. CHALL. EXP. — PART LXVII. — 1887.) XxX 83 



