58 PROCEEDINGS OF THE NATIONAL MUSEUM VOL. 113 
margin; exopod with 10 setae. Maxilla 2 and maxilliped with more 
setae on terminal portion than in P. cokerv. 
Exopod segment 2 of leg 1 produced at outer distal corner into 
rounded bulge; distal outer seta of exopod segment 3 slightly longer 
than proximal outer seta. Legs 2—4 with patterns of surface spinules 
shown in figure 10e—g; exopod sezment 2 and proximal part of segment 
3 of leg 2 with serrate outer margins. 
Connecting piece of leg 5 with nearly straight distal margin. 
Exopod segments 1 and 2 with stout outer setae; segment 2 with inner 
seta; segment 3 with 4 inner setae. Hndopod 3-segmented; segment 
2 with 2 rows, segment 3 with 2-3 rows of surface spinules; segment 3 
with 6 setae. Second basipod produced medially into rounded bulge 
with serrulate distal margin. 
Mate: Smaller and more slender than female, total length about 
0.50 mm. Rostrum articulated at base. Caudal setae as in female. 
Antenna 1, 17-segmented; antepenultimate segment produced into 
narrow triangular process. Right second basipod of leg 5 with row of 
surface spinules at level of origin of endopod. Longer inner spine 
of right exopod minutely serrate along middle third of convex outer 
margin. Right endopod more than 3 times as long as wide, apex 
emarginate. Left second basipod with row of spinules on distal 
margin. Inner membranous lobe of left exopod segment 2 broadly 
pyriform, middle part of inner margin crenulate; outer lobe much 
narrower, apex divided by V-shaped notch. Left endopod produced 
into lobe laterally near base, distal end bearing 5 jointed setae of 
which medial and lateral ones arise proximally to 3 central setae. 
Cotor: Typical specimens have a band of red pigment encircling 
the middle part of the prosome, extending ventrally from the base of 
the first maxilla to the base of the second swimming leg. The band is 
slightly wider dorsally. The eye is orange red. In some females 
the pigment may be more extensive, coloring most of the presome or 
even the entire body. In some of the latter specimens the pigment is 
heavier in the region with the band of pigment in typical specimens. 
Types: Holotype, female, USNM 104382; allotype, male, USNM 
104383; and 2 lots of paratypes (52 females and 7 females); from 
Thalassia meadow, Canal de Magiieyes, La Parguera, Puerto Rico, 
collected Mar. 25, 1959 (holotype), Nov. 25, 1959 (allotype and 7 
paratypes), and Feb. 23, 1959 (52 paratypes). 
The specific name rubrocinctus (Latin “ruber’’, red, and “‘cinctus,” 
girdled) refers to the red band of pigment of the prosome. 
The incompletely described P. reductus Nicholls (1944) from the 
Red Sea (Ghardaqa) appears to be very close to P. rubrocinctus. The 
female fifth legs of the 2 species are very similar, but endopod seg- 
ment 3 of P. reductus has only 4 setae, while that of P. rubrocinctus has 
