GEYLON ALPHEID A). 181 
One specimen, from the Pearl Banks ; February, 1911. 
The frontal region of carapace has a very characteristic appear- 
ance. There is no well-defined, sharply-pointed rostrum, but 
instead there is a broad lobe covering the bases of both antennules. 
This lobe is carinated in the mid-dorsal line. The region of the 
carapace covering the eyes is greatly arched and bulges out 
considerably. The proximal and distal antennular articles are 
subequal, and together are equal in length to the median article. 
From the anterior end of the proximal article there arises a well- 
defined bunch of long setze which point anteriorly and extend beyond 
the end of the peduncle. The antennular scale is poorly developed 
and is merely a broad lobe about half as long as the proximal article. 
The antennal peduncle is slightly longer than the antennular. 
The scale is short and does not reach much beyond the end of the 
median antennular article. 
The dimensions of the specimen are as follows :— 
a 10 Go mim: b§ = 3:0 mm. 
b! = 3-0 mm. 6° =) 325 mame: 
b? = 4-5 mm. é = 1075 mm: 
b= SG nim e! = 4:4 mm. 
b4 = 3:95 mm. e7 = 3-5 mm 
b> = 3:0 mm. 

The first pereiopods have no teeth on the palmar borders. 
Dimensions of second pereiopod :— 
m = 3960; 561 c* = 528; 462 
ci = 2409; 330 c® = 858; 495 
c? = 759; 396 jp = 1452; 528 
et == 561 > 429 fe = Goo Zak 
The third pereiopod has three spines on the posterior face of the 
carpopodite, and the distal end of this face also ends in a spine. 
There are seven spines on the propodite. The following are the 
dimensions :— 
m = 5082; 1221 p = 3531; 359 
c = 2640; 858 d= $90)= 204 
General Distribution.—Indian Ocean. 
ALPHEUS RAPAX, Spence Bate. 
(Plate VI., Fig. 4.) 
Alpheus rapax, Spence Bate. ‘‘ Challenger,” Macrura, 1888. 
One specimen, from Nachchikuda, Tamblegam. 
The median antennular article is more than twice as long as the 
distal. The proximal and distal articles are equal. The scale is 
not so long as the first article. 
