156 Annals of the South African Museum. 
pleopods but not those of 3rd pleopods well developed, peduncles not 
expanded ; 3rd uropod represented only by the lobe-lke peduncle. 
This genus differs from the other genera of the family in having 
long antennae, a palp on Ist maxilla and the peduncles of pleopods 
not expanded. 
PLIOPLATEIA TRIQUETRA Ni. Sp. 
(Plate XXVI. Figs. 18-24.) 
Body about as broad as deep. Head short, rostrum upturned, with 
a smaller tooth on either side. Eye round. <A small tooth on the 
anterior margin in front of eye, inferior margin keeled, ending in a 
small tooth at the antero-latero angle. 
Peraeon segment | equal to head, segments 1-7 each surmounted 
by a dorsal keel, strongest on Ist, where it is deeply bifid, on the other 
segments it occupies only the posterior portions, a flat horizontal, 
backwardly directed prominence on each segment just above the junc- 
tions with the side-plates. Side-plates not contiguous, Ist nearly as. 
deep as its segment, subtriangular, widening below and projecting 
forwards to antero-lateral angle of head, 2nd, 8rd, and 4th oblong, 
not quite twice as deep as long and not as deep as segments, antero- 
inferior angles of Ist to 4th rounded, inferior margin notched pos- 
teriorly, postero-inferior angles subacute, 5th longer than deep, strongly 
notched, anterior and posterior lobes acute, 6th and 7th similar to- 
5th but successively smaller. 
Pleon not strongly flexed, lst and 2nd segments with a dorsal tooth 
on posterior margin as large as that on 7th peraeon segment, a small 
subdorsal tooth on either side, 3rd segment smooth, unarmed except 
for the very obscure subdorsal teeth, 4th quite smooth, subequal to. 
3rd, postero-inferior angles of Ist to 3rd segments obtusely rounded. 
Telson transverse, twice as wide as long, apical margin straight,. 
postero-lateral angles rounded. 
First antenna reaching to about 6th peraeon segment, Ist joint 2 2nd, 
upper apex of both ist and 2nd joint projecting as an acute tooth, 
lower margin of Ist with one subapical tooth, 3rd jomt } 2nd, narrow 
and unarmed, flagellum longer than peduncle, 15 jointed. 
Second antenna reaching to middle of flagellum of Ist antenna, 
8rd joint short, 4th as long as broad, upper apex of both produced but 
not prominently so, 5th equal to 3rd and 4th together, narrow and 
unarmed, flagellum longer than peduncle, 11-jointed. 
Upper lip entire. 
Lower lip, lobes broad, apically truncate, inner lobes absent. 
