506 
MR. n. N. RIDLEY ON THE 
cell ; mucronate processes on the upper surface ; front wall 
of ocecium with a semicircular membranous area on the front 
wall. 
Fig. 2. 
Cellepora Ridleyi, n. sp. 
The ooecium of C. Ridleyi is remarkable in its shape and relations 
to the zooecium ; also there is a curious resemblance between the 
membranous area and the orifice of the zooecium. 
Log. Fernando Noronha. 
CRUSTACEA. 
By R. I. Pocock, 
Assistant in the Zoological Department, British Museum. 
Introductory Remarks. — The fauna is in all essential respects 
allied to that of the mainland and of the Antilles. The following 
wide-spread forms were, as might have been expected, met with: — 
Grapsus maculatus , Leiolophus planissimus, Hippa scutellata, 
Alpheus Rdivardsii, and Gonodactylus chiragra. There are two 
new species oi Alpheus, one of Ranulirus , and one of Stenopusculus 
(S. spinosus ). The last mentioned genus has hitherto only been 
known from the island of Mauritius ; its occurrence here, there- 
fore, is of great interest. A new freshwater Ostracod was also 
obtained. 
