REPORT ON THE BRACHYURA. 
81 
In all of its characters this species is nearly allied to Macrocceloma heptcicantha 1 from 
Puerto Portrero, but it may, perhaps, be distinguished, if the figure of Macrocceloma 
heptcicantha is to be trusted, by the form of the rostral spines, which in Macrocceloma 
heptcicantha are straight and separated by a considerable interspace, whereas in Macro- 
cceloma septemspinosci they coalesce at the base and curve laterally away from one another, 
so that the tips are strongly divergent. It is not a little curious that two species so 
nearly allied should have been described under names which are practically identical. 
Macrocceloma concciva, n. sp. (PI. X. fig. 2). 
Carapace longer than broad, moderately convex, and deeply concave upon the hepatic 
regions ; its dorsal surface is armed with about ten spines and tubercles, disposed as 
follows ; three small spines placed in a triangle upon the gastric region, of which the 
posterior and median one is the largest ; behind the median gastric spine are two small 
spines on the cardiac region and one on the intestinal region close to the posterior 
margin ; there is also a tubercle on the dorsal surface of each branchial region and a 
rather strong lateral spine. The lateral margins of the carapace are tuberculated, the 
tubercles being continued in an oblique series over the pterygostomian regions, nearly 
to the antero-external angle of the buccal cavity. The spines of the rostrum are short, 
in the adult less than one-fourth the length of the carapace, they are nearly straight, 
divergent, and separated by a triangulate interspace, but not widely remote at the base 
as in Macrocceloma subparallelci (Stimpson). The tubular orbits are laterally much elon- 
gated, and bear small spines or tubercles, placed one in front of and one behind the eye. 
The very largely developed basal antennal joint about equals the base of the rostrum in 
width, and bears four tubercles or small spines, of which one is placed at the distal 
extremity, and three on the outer margin. The merus of the outer maxillipedes is 
somewhat produced at its antero-external angle ; the exognatli is rather shorter than the 
endognath. The chelipedes, in the male, are rather slender, but somewhat elongated, 
exceeding the carapace and rostrum in length ; the merus-joint about equals the carpus, 
and is unevenly granulated and tuberculated on the margins. The carpus has a small 
tubercle on its inner margin ; the palm is slightly compressed, but not dilated nor 
carinated, and is granulated on its inner surface ; the fingers are about half as long as 
the palm, and bent downwards at an angle with it, they are curved, meeting only toward 
the tips, and are minutely denticulated on their inner margins ; the following legs are 
short, decreasing successively in length, with the joints subcylindrical, the dactyli 
terminating in a sharp claw. The body and limbs are covered with a short close 
1 Pericera heplacantha, Bell, Proc. Zool. Soc. Lond., p. 173, 1835; Trans. Zool. Soc. Lond., vol. ii. p. 61, pi. xii. 
fig. 6, 1841. 
(zool. chall. exp.— part xlix.— 1886 .) 
Ccc 11 
