180 ZOOLOGISCHE MEDEDEELINGEN — DEEL IIT. 




Specimens in the Museum: 
3 o', 29, Natoena Islands, A. L. v. Hasselt coll. 
PL Avail Hie. ‘1. 
These specimens, which I had provisionally referred to Ses. ocypoda 
Nobili, were sent by me to Dr. de Man, who informed me that they 
indeed belonged to the subspecies gracillima. The following are the prin- 
cipal points of difference from Ses. sylvicola de Man: 
1°. The front is somewhat broader in Ses. sylvicola, the outer orbital 
angle is obtuse and separated from the epibranchial tooth by a rather 
deep incision, the latter teeth are likewise obtuse and the distance 
between them is equal to that between the outer orbital angles; in 
Ses. ocypoda gracillima the front is narrower; outer orbital angles are 
more pointed and reach farther outward than the obtuse epibranchial 
teeth, that are separated off anteriorly by a narrow and small incision. 
In both species there is a trace of a second epibranchial tooth and 
the lateral borders of the carapace are diverging distally. 
2°. The surface of the carapace is more granulated and the regions are 
much better marked in Ses. ocypoda gracillima than in Ses. sylvicola. 
3°. In the abdomen of the co’ the last segment is as long as broad (at 
the posterior margin) in Ses. ocypoda gracillima, in Ses. sylvicola it 
is much broader than long; in the former species the posterior margin 
of the penultimate segment is twice the length of this segment, in 
the latter species, however, nearly three times this length. 
4°. The upper border of the mobile finger has a longitudinal row of 
10—11 tubercles, placed at regular intervals and extending to near 
the tip, in Ses. ocypoda gracillima; the first (proximal) 4—5 of them 
are cone-shaped and their axis is disposed perpendicularly to the long 
axis of the finger, the following tubercles are directed more obliquely 
forward, with their tip turned towards the end of the finger; besides, 
outside of this row of tubercles, there is a smooth longitudinal keel, 
running in the distal half of the finger. In Ses. sylvicola the longi- 
tudinal row consists of only 6—7 acute tubercles, all turned forward, 
towards the tip of the finger, and the longitudinal keel in the distal 
half of the finger is more feebly developed. ‘ 
The typical Ses. ocypoda is distinguished from the subspecies by a 
comparatively higher palm of the cheliped, by more numerous tubercles 
(14) at the upper border of the movable finger, all of them turned for- 
ward, by a shorter horny margin at the tip of both fingers (in the sub- 
species gracillima this horny margin occupies a third of the whole length 
