Pinnixa darwini — Garth 
41 
leg three two and one-third times as long as 
wide; leg four not overreaching merus of leg 
three. Male abdomen terminally broadened, tip 
triangular. Male first pleopod with a terminal 
projection and a subterminal swelling. 
DESCRIPTION: Carapace suboblong, width 1.87 
times length in male, 2.16 times length in 
female, lateral angles forming prominent shoul- 
ders from which sides drop away steeply, sur- 
face smooth and porcellanous, minutely punc- 
tate, and laterally fringed with plumose hairs. 
Gastrocardiac trench shallow, cardiac region ele- 
vated but uncrested, anterolateral margins, from 
lateral angle of carapace to cervical suture, form- 
ing a continuous, sharply defined, granular crest. 
Front truncate, slightly advanced beyond orbits, 
bilobed, lobes fringed. Orbits wide, inclined 
transversely in dorsal view, somewhat obliquely 
in frontal view, and completely filled with un- 
constricted eyestalk and cornea. 
External maxilliped with a short, broad pro- 
podus and a longer, spatulate dactylus broaden- 
ing distally; all segments with fringing hairs. 
Chelipeds of male well developed, merus tri- 
gonal, inner surface concave; carpus smooth and, 
like merus, hairy; manus widening distally, 
height .88 times superior length, uncrested, hairs 
of outer surface arranged principally in three 
rows, the lower extending onto pollex, the 
middle terminating at gape, and the upper con- 
tinuing on dactyl; fingers arching toward each 
other, pollex with three denticles, lower margin 
of hand sinuous; dactylus with two small teeth 
at middle of gape; gape choked with clavate 
hairs. 
Dactyls of ambulatory legs one and two 
straight and slender, of leg three broad and 
slightly curved, of leg four broad and straight. 
First leg narrower than, and reaching mid- 
dactylus of, second; second leg reaching mid- 
propodus of third; third leg longest, merus 2.33 
times long as wide, carpus and propodus corre- 
spondingly broadened, fourth leg greatly re- 
duced, its merus not over half the length of, its 
dactyl not overreaching, the merus of leg three. 
All legs conspicuously hairy. 
Male abdomen with somites four to six fused, 
edges sinuous; broadest at base of somite three, 
narrowest at base of somite five, broadening 
again to base of somite seven; seventh somite 
triangular in outline. Line of hair on somite two 
continued across sternum. 
Male first pleopod with a spinelike terminal 
process bent at a slight angle to the axis of the 
appendage; a bulbous subterminal swelling be- 
neath. 
Carapace of female broader than male, side 
walls less steep, shoulder less prominent; chelae 
more slender than male, palm narrower, fingers 
longer, gape less apparent. 
REMARKS: At the time of publication of the 
"Littoral brachyuran fauna of the Galapagos 
Archipelago” (Garth, 1946), but one species of 
Pinnixa, P. transversalis (Milne Edwards and 
Lucas) was known to inhabit the Galapagos 
Islands. The basis for this record, and for the 
diagnosis and figures presented {ibid.: 498, pi. 
84, figs. 6 and 8) was a male and female from 
Darwin Bay, Tower Island, 40-70 fathoms, 
"Velero III” station 783-38, identified by the 
late Steve A. Glassell, together with the tubes of 
Chaetopterus variopedatus (Renier) from which 
they were taken. Subsequently, two other lots of 
Pinnixa from the Galapagos Islands, both of 
Hancock expeditions origin, have come to hand: 
the first, a single male from Tagus Cove, Al- 
bemarle Island, 12 fathoms, December 10, 1934, 
"Velero III” station 330-35, identified by the 
late Mary J. Rathbun as P. transversalis, and the 
present group of two males and one ovigerous 
female, which, although coming from the same 
locality and station as the Glassell-identified 
specimens, represent a totally different and 
hitherto undescribed species. 
The proposed new species finds its most 
closely related species in Pinnixa faxoni Rath- 
bun (1918: 133, pi. 29, figs. 4-7, figs. 77a, b), 
type locality Trinidad, of which it is almost cer- 
tainly the Pacific analogue. According to Dr. 
F. A. Chace, Jr., curator of marine invertebrates, 
U. S. National Museum, who made the compari- 
son, the carapace, including the ridge across the 
hinder part, is practically identical with some of 
the type series of P. faxoni. Only three impor- 
tant differences between the two species were 
noted: first, the fingers of the chelae gape much 
more widely in the Galapagos species than in 
P. faxoni, those of the male of P. faxoni being 
very much like those of the female of the pro- 
posed new species, those of the female of P. 
