’s RIJKS MUSEUM VAN NATUURLIJKE HISTORIE — LEIDEN. 195 
7°. The carapace is, like the ambulatory legs, reddish-yellow in Ses. 
dentifrons. 
I have examined 4 adult specimens of Ses. rotundata, which were 
caught during the ,,Siboga’’-expedition to the Hast-Indian Archipelago, 2 
d and 2 ©, and the study of these specimens has fully convinced me of 
the correctness of de Man’s views regarding the minute differences here 
enumerated: these may be ascribed to sexual differences. In nearly all 
respects my © of Ses. rotundata agree with the typical specimen of Hess, 
and the © with Ses. dentifrons ; the only restriction being that the minute 
dentiform processes, mentioned by de Man and figured by him, both in 
the case of the {/ and of the ©, at the free margin of the front are in 
my specimens only developed in the © and even here very inconspicu- 
ously; besides there are at either side of the distinct, though narrow, 
median sinus (according to de Man this emargination is, however, broad 
and shallow) a group of three rounded tubercles, disposed in a single 
row, the two outer ones corresponding to the inner dentiform projections, 
spoken of, but lying immediately above these projections, on the surface 
of the front, not at the free border; these tubercles are only distinct, 
however, in the {. 
Finally, though the preservation in alcohol during 17 years has much 
discoloured my specimens, it is still to be observed, that the carapace in 
the © has a darker hue than that of the o’, and, besides, the difference 
in hairiness of the propodites and the dactyli of the ambulatory legs 
between both sexes, exactly agree with the finds of de Man in this respect. 
Though I do not hesitate in regarding Ses. dentifrons only as the Q of 
Ses. rotundata, | am inclined to regard the subspecies papuo-malesiaca of 
Nobili (Ann. mus. civ. stor. nat. Genova, (2) t. 20 p. 268, 1899) as an 
individual variation. Nobili distinguished his subspecies by the following 
characters : 
1°. Inside the denticulated crest along the upper border of the palm, 
there are two small similar and subparallel crests, forming an angle 
with the large and continuous crest along the upper border. Nobili 
admitted, that these small crests may also exist in the type-specimens 
of de Man, though they were not mentioned by the latter author. 
2°. The front is distinctly emarginated by a median sinus; according to 
de Man there is only a broad and shallow emargination. 
3°. The greatest breadth of the carapace exceeds the length in the median 
line; in the typical specimens (de Man) these dimensions are nearly 
equal. 
4°, The dimensions taken by Nobili (le. p. 510) indicate, that the pos- 
