622 PROCEEDINGS OF THE NATIONAL MUSEUM VOL. 113 
portion; outer margin crenulate but unarmed in specimens more 
than 6.0 mm. long, spinose in specimens less than 3.5 mm. long. 
Fingers meeting throughout and pubescent on inner, lower margins. 
Merus of first walking leg armed on dorsal margin with five or 
six, rarely seven, spines and fringe of plumose hairs and with one 
strong spine at distoventral angle below acute or spinose lobe; no 
spine at upper distal angle. Merus of second leg with five or six 
dorsal spines and one distoventral spine below rounded lobe which 
may occasionally bear a second spine at its lower angle; upper distal 
angle acute but not dentiform. Merus of third leg with four or five, 
rarely two or three, dorsal spines and unarmed at rounded distoventral 
angle; upper distal angle dentiform but not spinose. 
Telson composed of seven plates. 
MEASUREMENTS: Carapace of male holotype, 7.9 mm. long and 
7.4 mm. wide. Carapace lengths of Clipperton Island males, 3.2-8.0 
mm.; of females without eggs, 2.0-5.2 mm.; of ovigerous females, 
5.0-9.8 mm. 
Cotor: Specimens preserved in ethyl alcohol retain much of 
original color pattern, even after 20 years. Dorsal surface of carapace 
and chelipeds spotted with red, sometimes to such a degree as to 
form a checkerboard pattern on carapace. Ventrally, sternum and 
appendages everywhere deep crimson. 
Remarks: Most previous authors have believed this species to be 
identical with the West Indian P. marginatus Stimpson. It is dis- 
tinguished from that species, however, by the much less transverse 
lateral lobes of the front and by the presence of only one, rather 
than two, epibranchial spines on each side of the carapace. 
The species is named for Miss Janet Haig who has added so much 
to our knowledge of the porcellanid crabs, especially those from the 
eastern Pacific, and who has provided valuable information for the 
present study from material in the collections of the Allan Hancock 
Foundation. 
DistrisuTIon: In addition to the Clipperton collections, material 
of the typical form of P. haigae has been examined from the Tres 
Marias, Clarion, and Galapagos Islands. Miss Haig (in correspond- 
ence) states that there are also typical specimens in the Hancock 
collections from the Gulf of California and Revilla Gigedo Island. 
In general, specimens of the analogous form found on the mainland 
from Mexico to Colombia are more spinose than the typical form, 
especially on the supraorbital margin and the outer margins of the 
carpus and hand of the chelipeds. It is very possible that further 
study will prove the mainland form to be specifically distinct. 
