1g12.| R. B. SEyMOUR-SEWELL: Surface-Living Copepoda. 3.45 
endopodite is bifid, the external process being the longer of the 
two. 
7” Total length 2°86 mm. 
The head and thorax resemble those of the female, with the 
exception that small rostral lenses are present. 
The abdomen consists of five segments, of which the 3rd is 
the longest, the furcal rami are symmetrical and the proportional 
length of the segments and furca are 7: 5: 10: 5: 5: 15. 
The left 1st antenna resembles that of the female. The ght 
forms the usual grasping apparatus. The kneé-j oint is between the 
18th and 19th segments. The 17th segment is produced on its 
anterior surface as a low crest, terminating in a short spine dis- 
tally. The r8th segment carries a toothed-plate, which is pro- 
longed proximally for a short distance over the 17th segment, 
and is armed with a double row of fine teeth. The roth segment 
bears two tooth-plates each armed with fine teeth, and is pro- 
longed distally as a sharp spine. The proportional lengths of the 
end segments are as follows :— 
PUA GeO d ene Ge UO-2 1 22-215. 
8 Cent 2h spec Ole 26. 
The 9th—r12th segments each carries a seta-like spine on the 
anterior border. 
The 5th pair of legs is as figured. Instead of a single process 
on the proximal segment of the claw, it bears two spines, and prox- 
imal to the spines are a pair of small knot-like projections on the 
margin. The distal segment is broad and ends in a blunt club- 
like protuberance. The left leg terminates in a long segment, 
bearing the usual spine and two processes terminally, and about 
two-thirds of the distance along its posterior surface arises a 
serrated spine. 
P. andersoni. Stage 3. 
Pl. xx, figs. 7—9. 
@ At this period of its existence the animal is as mentioned 
before, sexually immature, andin consequence we find that the 
abdomen consists of 3 segments, one more than in the mature 
female. As regards the appendages, these are for the most part 
the same as in the adult, and even in the case of the 5th pair of 
legs there is no very marked difference ; the endopod is, however, 
a “trifle shorter and its two terminal processes have not yet as- 
sumed their final delicate shape 
o In the male, as was pointed out in the case of Labidocera 
euchaeta, there are very considerable differences between this 
stage and the next. 
The abdomen consists of 4 segments only, of which the third 
is the longest. 
The left 1st antenna exactly resembles that of the female ; 
the right, though quite unlike that of the adult, yet has begun to 
