’s RIJKS MUSEUM VAN NATUURLIJKE HISTORIE — LEIDEN. — 175 



1910. Sesarma (Sesarma) minutum Rathbun. K. Dansk. Vid. Selsk. Skr., 
7. Raekke, Afd. 5 n°. 4 p. 327 — Gulf of Siam. 
76. Sesarma (Sesarma s.s.) modesta de Man. 
1902. Sesarma (Sesarma) modesta de Man. Abhandl. Senckenb. Gesellsch., 
Bd. 25 Heft 3 p. 511, pl. 19 f. 8 — Ternate. 
PRPC e Bic. 1: 
I have before me some specimens from Nias, belonging to the Am- 
sterdam Zoological Museum and, besides, one specimen, collected by the 
ysiboga’”’-Expedition. All these specimens are Q, so that the determination 
presents great difficulties; on sending the material to Dr. de Man, I 
learned that these specimens are to be referred to the present species. 
As the © is not yet known, I shall try to indicate the differences from 
the co’, having chosen the ,Siboga”-specimen as base of my description. 
De Man compares his species in the first place with Ses. angustifrons 
A. Milne-Edwards, from which it is distinguished, however, by a much 
shallower emargination of the front, the lack of a transverse row of 
granules at the inner surface of the palm, but especially by the much 
broader and shorter walking legs, which give this species in my opinion 
a much greater likeness to Ses. edwardsi and Ses. moeschii, both des- 
eribed by de Man, and to Ses. impressa H. Milne-Edwards. 
The carapace in the Q is rather strongly conyex in a longitudinal 
and somewhat less so in a transverse direction; the branchial regions are 
very much declivous. Regions well marked, as in the o’, especially the 
transversal furrow marking the posterior margin of the mesogastric area ; 
this furrow is not interrupted in the middle, broadened and deepened at 
both ends; the grooves that mark the protogastric regions laterally, ap- 
parently distinct in the ©’, are lacking in my specimens. The mesogas- 
tric region itself is divided by a concave transverse groove into two 
parts, the anterior one of which is the larger. Anterior cardiac region 
separated by slight grooves from the branchial regions, in a similar way 
the intestinal region is separated off, but here the lateral boundaries 
are much less distinct. Postfrontal lobes straight at the fore margin, sepa- 
rated by very narrow grooves; lateral lobes about */, times as broad as 
the inner lobes '); the former with posterior lobe. All the lobes, espe- 
cially the median ones, with a few transversely-elongated or rounded 
tubercles; similar rounded tubercles are also found on the much depressed 
1) De Man says, that the fore margin of these outer lobes is transversely grooved, but 
more continuously so at the right lobe; in the © this transverse furrow is equally developed at 
both lobes, 
