1912.] R. B. SEYMOUR-SEWELL: Surface-Living Copepoda. 3333 
external margin, and the 2nd joint is devoid of spines. ‘The 
endopodite is two-jointed and bears no spines; the last segment 
bears 5 setae. 
The 2nd pair of legs. ‘There are no spines on the basal joints. 
The segments of the exopodite have the usual marginal and end 
spines, and in addition the Ist segment of the exopod bears a 
transverse row of spines on its outer and posterior aspect. The 
2nd segment bears a slightly oblique row of 4 spines posteriorly 
and the 3rd segment bears a corona of spines on its posterior 
surface. 
The 3rd and 4th patrs of legs are almost exactly similar. 
There are no spines on the basal joints. The Ist segment of the 
exopod bears a row of spines on the outer and posterior surface 
distally in the 3rd leg; this is absent in the 4th. The 2nd joint 
has a row of 4 spines posteriorly, and the 3rd joint has a corona 
of fine spines in addition to the marginal row. The 2nd joint of 
the endopodite has a row of spines on its posterior aspect and a 
transverse corona of spines on its outer and anterior surface. 
In the 2nd—4th legs the endopod bears 2 setae on its 2nd 
and 7 on its terminal joint. / 
The 5th pair of legs is the same as in P. dubia, but in a few 
specimens a third small segment was intercalated between the 
usual two. 
@¢ Total length 1°r mm. 
The cephalo-thorax is the same as that of the female. The 
abdomen consists of five segments and its length is contained 2°5 
times in that of the cephalo-thorax. The proportional lengths of 
abdominal segments and furca are 10: 20: 16: 16: 12: Io. 
The rostrum consists of two short stout spines. 
The 1st antennae reach a point a short distance behind the 
posterior border of the 5th thoracic segment. As usual in adult 
males of this genus the basal segments are fused together, so that 
there are only twenty joints present. The relative lengths are as 
follows :— 
Segments— 
I-2. 3-6. 7-8. 9. 10. If. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 
Gand Geeoe NG On 7 oe 1OseG 4s Lin Tietta 10) El, .log tral hte aee 
The 2d antennae resemble those of the male of P. parvus, 
and the exopodite terminates in a nipple-like projection. 
The 1st pair of legs. ‘There appear to be no spines on the tst 
basal joint ; basal 2 as usual bears an internal seta. ‘The Ist joint 
of the exopodite has no marginal spine, the 2nd carries a trans- 
verse row of small spines and the 3rd has a row of delicate 
spines on the proximal part of the external margin. The terminal 
spine is long and slender, being longer than the whole exopodite. 
The 2nd—gth pairs of legs are the same as in the female. 
The 5th pair of legs. As usual that of the left side is con- 
siderably the larger and possesses four segments in addition to the 
enlarged basal portion. The proportional lengths of these seg- 
