320 PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 
coxal region ; t. 1 and t. 2 each about the length of/*.; ts. 1 short, 
triangular, emarginate at distal border ; ts. 2 rather slender for this 
genus, somewhat more than half as long as t. 2, only slightly arcu¬ 
ate, projection at the distal end slight, no differentiation into heel 
and sole except in the size of the spines on these two regions; cl. 
strong, curved, half as long as ts. 2 ; aux. cl. well developed, fully 
half as long as cl. The femoral joint of the female is broader than 
that of the male, and is broadest near the middle (pi. 21, fig. 4), while 
in the male it is broadest distally (pi. 21, fig. 14) ; in both sexes the 
dorso-distal corner projects and is armed with a spine. The margins 
of/*., t. 1, and t. 2 are more or less irregular and wavy. The first and 
second coxal joints of the male are armed with prominent tubercles 
bearing spines (pi. 21, fig. 14), three of these regularly (Jccurring 
distally on the dorsal side of c. 1, and one or two laterally on c. 2 ; in 
the female these tubercles are much reduced, the two lateral ones 
at the distal end of c. 1 being best represented, while the middle 
tubercle is low and does not bear a spine (pi. 21, fig. 4). The remain¬ 
ing joints of the legs are but sparsely armed with short spines, but 
have longer ones in the usual positions, i. e ., one near the distal end 
on the dorsal margin of each t. 1 and t. 2, and on the dorsal margin 
of ts. 2. The ventral surface of ts. 2 bears a number (about 7 to 
10) of comparatively stout spines, those on the proximal end being 
somewhat longer and representing the only indication of a heel ; 
ts. 1 bears one strong spine and several small ones. The genital 
protuberance on the ventral side of c. 2 of the third and fourth pairs 
of legs in the male is short, conical, and unarmed (pi. 21, fig. 11) ; 
genital openings of the female, as usual in the genus, not on protu¬ 
berances, but in a corresponding position on all four pairs of legs. 
Length about 1.3 inm., extent nearly 6 mm. The males average 
slightly smaller than the females. 
Color nearly white. Integument thin, with comparatively few 
cuticular cavities. 
Immature specimens. — The four immature specimens examined 
were of nearly adult size, but the ovieera were not yet fully devel- 
oped and the chelifori were still in a chelate condition (pi. 21, fig. 
12). The fingers of the chelae are about as long as the palm ; 
strongly arcuate, the movable finger slightly overlapping the other. 
This is probably the stage- immediately preceding the last moult 
before the adult condition is attained. 
