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thirds; propodus slightly longer than carpus; fingers parallel, slightly 
deflected from the line of the palm, without teeth, their inner and outer 
surfaces densely pubescent. 
Manus of the second pair minutely spinulose to the base, of the fin- 
gers; carpus and meros spinulose, the spinules larger on the under 
surface, where they form dlstinct longitudinal rows. 
Posterior legs smooth, cylindrical, sparsely pubescent. 
Terminal segment of abdomen with seven spinules, three at the tip 
the central one fixed, the lateral ones articulated, and two pairs situ- 
ated farther forward, the anterior pair at about the middle of the 
length of the segment. 
Three or four specimens were taken in Mulege River, on the West 
coast of the Gulf of California, by W. I. Fisher. 
This species closely resembles P. dasydactylus Streets (Proc. Phil. 
Acad., 1871, 225) which is quoted by Kingsley, in his List of North 
American Caridea (Bull. Essex Inst., Vol. X, Nos. 4, 5, 6) as a syno- 
nym of P. forceps M. Edward. The principal differences traceable are 
in the proportions of the joints of the first pair of legs, the manus in 
the present species being shorter than in P. dasydactylus, in the greater 
length of the articulations of the second pair in this species, as com- 
pared with their thickness; and in the spines of the terminal abdomi- 
nal segment, which dre only five in Dr. Streets’ species. 
The differences are so small, and the resemblances so great, as to 
suggest the possibility of actual near relationship; and it is not im- 
probable that in this form we meet with the descendants of such of 
the Atlantic P. forceps as penetrated into the Pacific when the oceans 
were connected at what is now the Isthmus of Panama. 
The female resembles the male, except in the second pair of limbs, 
which are much smaller, smooth, shorter, and more slender, and have 
the proportions of the joints reversed, the manus shorter than the 
carpus, and the latter shorter than the meros. 
The specimens were obtained in August, and the females were 
loaded with ova. 
The teeth on the upper side of the rostrum vary somewhat, the tip, 
which is blunt in one specimen, is bifid in another, and one of the 
males has only eight teeth on the upper edge. 
Following are the dimensions of a male and female : — 
3 ? 
Totallength, . - . ; c - 105 millims. 82 millims. 
Length of carapax, including rostrum, . bil ue 37 ee 
es ‘* flagellum of antennae, 5 . 110 gs Vout = 
# “* outer flagellum of antennule, . 90 oc — ee 
$6 ‘s first pair of legs, é : ‘ 39 ee 25 UG 
