a neio Am phi pod Species. 511 



Pleon-segments 1 and 2, hind margins straight, postero- 

 lateral angles obtuse. Pleon-segment '6 is the most easily 

 observed distinguishing character of the species; in longipes 

 the posterior lobe is acutely upturned, rounding gradually 

 below into the interior margin, while in aUeni, in all stages 

 of growth, the lobe is acutely produced below as well as 

 above, the margin between the points being deeply concave 

 (fig. 2). 



Antennoe. — Superior antenna : peduncle as in longipes ; 

 flagella longer in proportion ; ■primary flngellum in the large 

 female considerably more tliau twice the length of the 

 peduncle, 18-joinled ; accessory flag ellum nearly one-thiid 

 the length of the primary, G-jointed. The largest male in 

 Mr. Tattersali^s collection had 22 joints in the primary, 6' in 

 the accessory. 



Inferior antenna shorter than the superior in the female ; 

 flagelluni 15-jointed. In the male the tiagellum is tiliform, 

 t)2 joints in the largest specimen, 46 in the smallest. 



Ural parts. — Lower Up much as figured by Sars for longipes^ 

 densely covered with fine hairs, as is also the upper lip. 



Mandibles (tigs. 3 and 4) nmch as in the type species, but 

 distinguished from it by the different proportions of the joints 

 of the palp. Cutting-plates large, rounded, with a small 

 recuived tooth above. The left mandible (fig. 3) has a very 

 sn:all accessory plate, the margin of which is divided into 

 three rounded teeth. Spine-row with three spines. Molar 

 large, prominent; crown reniform in shape, transversely 

 ridged. The palp is veiy long and slender, the second joint 

 longer in proportion than in longipes, twice the length of the 

 third, with a row of graduated setitorm spines crossing its 

 distal end diagonally ; third joint narrow, tapering to the tip, 

 with a row of serrate spines on the inner margin, and an 

 apical cluster of four longer ones setting out at a different 

 angle. 



Maxilla 1 (fig. 5). — Inner plate tipped with 2 plumose 

 setse; outer plate large, apex obliquely truncate, with 11 

 strong,, flat, dentate spines, 10 of which are arranged close 

 together in two lows, the remaining one being inset lower 

 down on the inner margin. Pa//> large and broad ; apical 

 margin rounded and beset with 7 small stout teeth and 1 

 short spine. 



Maxilla 2 as in longipes. 



Maaillipeds (fig. 6). — In/ier p)late: apex truncate, with 3 

 short stout teetii ; a row of plumose setje starting from the 

 outer angle runs halfway down the inner margin. Outer 

 plate very large, furnished with 2 stout teeth apically and a 



