1921] Schmitt: The Marine Decapod Crustacea of California 175 
Kry To CALIFORNIA GENERA OF THE PORCELLANIDAE 
I. Epimera (pleural, subbranchial, or lateral portions of the carapace) entire. 
Chelipeds equal or subequal, broad and flattened; carpus more or less 
elongated. 
Petrolisthes, p. 178. 
II. Epimera posteriorly broken up, the posterior portion of the subbranchial 
region subquadrate and separated from the larger anterior portion by a 
membranous or cutaneous interspace. Chelipeds unequal, thick, and more 
or less roughened; carpus short. 
Pachycheles, p. 175. 
Genus Pachycheles Stimpson 
Carapace rounded, ovate, at least as broad as long, with lateral margins marked 
by an elevated line; front somewhat deflexed, a little prominent at the middle, and 
subacute, but never dentated, with its apex concealed by pubescence; epimera 
posteriorly broken up, the posterior portion of the subbranchial region subquadrate 
and separated from the larger anterior portion by a membranous or cutaneous 
interspace. First or basal joint of antennal peduncle produced and joined to the 
margin of the carapace; second joint at some distance from the orbit. Chelipeds 
unequal, thick, and more or less roughened, carpus short. 
The species of this genus, listed below, in general appearance are all very much 
alike; the carapace is round-ovate; front short, depressed, and pubescent; cheli- 
peds unequal, either the right or left the larger; carpus with two to three rows 
of the granules more prominent than the rest; ambulatory legs more or less 
pubescent on upper margin; propodi and dactyli spinulous below. 
Key TO THE CALIFORNIA SPECIES OF PACHYCHELES 
I. Chelipeds rugose, granulated, and tuberculated above, and furnished with a 
prominent, naked, granulated tubercle on the median distal portion of 
the palm, near the gape of the fingers. Lateral (not terminal) plates of 
telson in one piece. 
A. Chelipeds covered with a thick, dense, even, velvety pubescence, which 
also fills the gape between the fingers of the larger hand. (Santa 
Monica Bay to San Diego.) 
holosericus, p. 177. 
B. Chelipeds with only a few scattered, coarse hairs on upper surface, and 
with only a few if any in the gape of the fingers. 
rudis, p. 176. 
II. Chelipeds evenly rounded and not tubereulated above, quite uniformly granu- 
lated; granules hidden beneath a short, thick pubescence, interspersed with 
numerous tufts of longer hairs; gape between the fingers of the larger 
hand filled with a dense, bushy pubescence. Lateral plates of telson com- 
posed of two pieces, a small rounded proximal portion, and a large distal 
portion which alone constitutes the lateral plate of the other species of 
Pachycheles here listed. (Not found south of San Francisco Bay.) 
pubescens, p. 177. 
