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on 
252 CRABS OF THE FAMILY PERICERIDA—RATHBUN. 
from which it differs also in the protuberances of the carapace. In its 
proportion it approaches nearer the figure given by Aurivillius (loc. cit.). 
A detailed description of the individual is given below, as a series may 
in the future connect these two species. The two small specimens in 
the collection offer no essential differences. 
Carapace with a scattered pubescence, subtrapezoidal, concave at 
the hepatic region; outline of branchial region rounded. The protu- 
berances of the carapace are as follows: three tubercles forming a tri- 
angle on the gastric region, the posterior one large and on the median 
line, the other two inconspicuous; a spiny tubercle on the cardiac 
region; another longer on the intestinal; on the branchial region, a 
prominent slender spine just above the margin and behind the broad- 
est part of the carapace; above this spine another very small; on the 
lateral margin an irregular row of small spines and spiny tubercles, 
one on the hepatic and about five on the branchial, the one next to the 
last being the longest, but only two-thirds as long as the epibranchial 
spine; a branch of this marginal row is continued on the pterygosto- 
nian region, which is covered with small tubercles. 
Rostrum thin, almost straight; horns separated by a triangulate 
space; their distal half slender, acuminate; proximal half broad, sub- 
triangular, with convex outer margin. 
Orbital sheaths long, prominent. Distance between the tips of the 
postocular spines a little greater than the width of the carapace at the 
branchial regions exclusive of spines. On the upper orbital margin 
there is a tooth above the postocular; and a small spine on the lower 
margin. Basal joint of external antenne armed with two sharp spines. 
Chelipeds moderate. Merus tuberculous, with a row of four small 
spines above. Hands long, compressed, finely pubescent. Fingers 
arched, partially gaping; distal third brown. First pair of ambulatory 
legs barely reaching the manus. 
Entire length, 25; length of rostrum, 6; width at the branehial 
regions, without spines, 15.6; length of cheliped, 28; length of first 
ambulatory leg, 20 millimeters. 
M. eutheca has been collected at the Tortugas, Florida Straits, 12 to 
115 fathoms, Santa Cruz, besides other localities. 
Macrocceloma tenuirostra, sp. hoy. 
Plate xxxi1l, fig. 1. 
Carapace much lorger than broad, subrectangular, slightly convex; _ 
finely pubescent. .Epibranchial spine short, slender; posterior margin 
with a slender upturned spine. Dorsal surface with a blunt median 
spine above the posterior margin; a tuberele occupying the eardiae re- | 
gion; another far back on the gastric region; remainder of the surface 
with small depressed tubercles, which on the antero-lateral margin form | 
an indistinct row. 
