4 
PROCEEDINGS : BOSTON SOCIETY NATURAL HISTORY. 
fifth pair nearly their own width apart, others intermediate. Cheli- 
cipeds very large, subequal,— in the male specimen the left only is 
present,— subchelate, smooth, margins hairy; meros nearly (male) 
or twice (female) as long as ischium, external margins acute, teeth 
at inner ventral angle ; carpus triangular in outline, smaller in 
male ; propodus articulates with carpus by two tubercles, length 
twice (male), one and a half times (female) the breadth, margins 
acute; the “thumb” delimits an occludent margin half as long as 
the joint; acute with one large tooth and many finer teeth ; dactylus 
bent at base at almost a right angle, arcuate, with sharp margins, 
the outer of which is fringed with long hairs. Second pair of 
pereiopods (pi. 1, fig. 11) short, flattened, maxilliped-like, hairy on 
ventral margin; outer joints short; dactylus with long hairs. 
Third pair of pereiopods longer than fourth or fifth, but all three 
pairs with long propodi and slender, arcuate dactyli. 
Measurements of limbs in millimeters. 
Segment. 
Total length. Ischium. 
Meros. 
Carpus. 
Propodus. 
Dactylus. 
Chel. (Jc ) $ 
17.8 
2.5 
3.1 
1.2 
6.5 
4.5 
? 
21.3 
2.3 
r. 4.5 
2.3 
r. 7.0 
4.0 
1. 4.7 
1. 6.8 
II ( l ) 
$ 
9.0 
1.5 
3.5 
1.1 
1.8 
1.2 
? 
10.5 
1.0 
3.7 
1.5 
2.0 
1.3 (?) 
III (m) 
$ 
12.5 
2.0 
4.0 
1.9 
3.2 
1.5 
? 
14.9 
2.3 
4.0 
2.0 
3.6 
2.0 
> 
HH 
s 
11.0(?) 
1.9 
3.0 
1.8 
2.9 
_ 
$ 
12.5 
2.0 
3.0 
1.7 
3.4 
1.4 
V (o) 
8 
10.0(?) 
1.9 
3.0 
1.8 
2.9 
_ 
? 
— 
— 
3.0 
2.0 
3.5 
1.5 
Width of propodus of k, ^ 3.5 ; ? r. 4.1, 1. 4.4 mm. 
Occludent margin of propodus of /•, $ 3.8 ; $ 3.7 mm. 
Gills eighteen, phyllobranch, with narrow, linear plates as in 
Callianassa; plates broader on anterior podobranchs. No pleuro- 
branchs. Arthrobranchs, 13; the one on segment g small; both 
gills of the pairs on h and i — second and third maxillipeds_sub¬ 
equal; anterior gill of remaining pairs smaller than posterior. 
Podobranchs, 5; large on h and i ; small on remaining segments. 
Mastigobranchs, 7 ; broad on g and i (pi. 1, fig. 14), slender on /i, A', l • 
(pi. 1, fig. 15), m, and n, weakest on n (pi. 1, fig. 16). A calcified 
