28 
A. 0. WALKER. 
■*? 
The tooth on the first joint of the upper antennae is much longer in the large 
specimens than is shown in Stebbing’s figures. This is probably only a matter of age. 
Iphimedia echinata. (PI. 10, fig. 16.) 
Iphimedia echinata, A. 0. Walker, Ann. and Mag. Nat. Hist. XVIII. (1906), p. 150. 
/cpr ■ '/ W.Q., 24 Sept., 1902, Hut Point, one, large ; 24 Aug., 1903, Hole 12, D-net, three, 
large, 30 mm., and about twenty-five, young ; 26 Sept., 1903, Hole 12, D-net, one, about 
45 mm. long and 15 mm. across the back. 
First segment of the mesosome longer than the second ; the next four segments are 
longer than the second and subequal ; the posterior angles of the first two are almost 
right angles, and of the next four acute. The fifth segment has sometimes a few small 
teeth on the hind margin ; the sixth has more, and the seventh is dorsally depressed, 
and is longer than any of the other segments in the middle, but greatly narrowed down¬ 
wards, with the hind margin more coarsely dentate. The pleon segments have 
strongly dentate, dorsal carime, with smaller teeth on each side, and on the hind 
margins ; the posterior angle of the second is acute and upturned, and that of the third 
similar, but longer, and with a much longer curved tooth above it. The first urus 
segment is as long as the two next united, and has a dorsal depression followed by a 
group of upright teeth; the second and third are smooth, except for a tooth on each 
side of the telson. The first three pairs of side-plates narrow downwards to a point, 
the second and third curved ; the fourth, fifth and sixth have a strong tooth with 
serrate edge directed outwards. The number of teeth appears to vary considerably in 
different specimens. 
Head : Rostrum as long as the rest of the head, acute, decurved; ocular lobes 
rounded ; eyes prominent, round, colourless. 
Upper antennse : First joint with two distal teeth on the upper side ; second joint 
with a serrate tooth reaching almost to the end of the first joint of the fiagellum on the 
upper margin, and a short one on the lower ; third joint short. In a young specimen 
a rudimentary appendage was seen, but in a larger (though not adult) this was only 
indicated by tw T o setse. First joint of the flagellum as long as the next three.* 
Lower antennse subequal to the upper ; second and third joints subequal; the 
three peduncular joints have the upper margins produced; the basal joint has a 
prominent curved tooth on its upper side. 
Mandibles, without molar tubercles, different ; one, having the simple cutting 
edge oblique, obscurely dentate, with a tooth at the lower angle; the other having the 
cutting edge more strongly dentate, with a peculiar secondary apparatus in the form of 
a hollow chitinous cylinder with a smooth periphery. First joint of the robust palp 
shorter than the second, which is subequal to the third. 
* In the specimen figured the antenna was curved upwards. 
