234 ZOOLOGISCHE MEDEDEELINGEN — DEEL III. 



Ses. (Hol.) festae Nobili. 
Ses. (Hol.) occidentalis Smith. 
Ses. (Ses.) ophioderma Nobili. 
Ses. (Ses.) rhizophorae Rathbun. 
Ses. (Ses.) sulcata Smith. 
Of these 9 species 4 belong to Holometopus and 5 to Sesarma s.s. In 
Miss Rathbun’s key to the American Sesarmae, above referred to, these 
species are included '), with exception of Ses. biolleyi, festae, ophioderma 
and rhizophorae, that were afterwards described by the author herself 
and by Nobili. The majority of the species are from Central America; 
at the coast of California the genus does not seem to be at all répresen- 
ted, and south of Ecuador I know only of one single species (Ses. bar- 
bimana from Peru) *). I have scarcely any doubt, that further collections 
from these little-explored regions will furnish several new forms of 
Sesarma. 
None of the West American species of this genus are contained in 
the Leiden Museum. 
III. Key to the Indo-Pacific species of Sesarma, Metasesarma, 
Sarmatium and Clistocoeloma. 
The four genera may be characterized by the following key: 
1 Outer antennae not excluded from the orbit. 2 
Outer antennae excluded from the orbit: the inner border of the 
latter with a prominent triangular lobe, that meets a projection of 
the lateral corner of the front, though there may remain a narrow 
gap between the inner orbital lobe and the front. 3 
2 Carapace flattened or convex, with distinct and deeply separated 
postfrontal lobes; front vertically and generally abruptly deflexed ; last 
segment of abdomen of o usually shorter than broad at the base, that 
of © (in adult specimens) deeply impacted in the foregoing segment. 
Sesarma. 
Carapace very convex; postfrontal lobes rounded-off anteriorly, not 
prominent; front obliquely deflexed, gradually declivous ; last segment 
of abdomen of cj longer than broad at the base, that of 9 not deeply 
impacted in the penultimate segment. Sarmatium. 
1) Ses. aequatorialis has heen afterwards added by the author on p. 112. 
2) In Miss Rathbun’s list of the Decapod Crustaceans from Peru and the adjacent coasts 
(Proc. U. S. Nat. Mus., v. 38, 1910, p. 590) six of the species here enumerated are recorded. 
In this paper the whole coast from Panama to Chiloé is taken into account, 
