CRUSTACEA OF THE MERGUI ARCHIPELAGO. 293 
the peduncle of the external antenne; the basipodites are 
armed with an acute spine. The carpopodites of these legs 
are scarcely twice as-long as the hands, the fingers of which are 
about as long as the palm. The third pair of legs, the last of 
the chelate, are still longer than the two anterior pairs, for they 
reach nearly to the distal ends of the penultimate joints of the 
peduncles of the internal antenne, projecting with the whole 
hand beyond the. peduncles of the outer antenne. The basi- 
podites of the third legs are also armed with a slender, acute 
spine, and their carpopodites are slightly longer than twice the 
length of the hands, the fingers of which are almost as long as 
the palm. 
As in other species of this remarkable genus, the legs of the 
last two pairs present a different structure in the male and in the 
female. The legs of the fourth pair of the male are much 
shorter than those of the third pair, reaching only as far forwards 
as the anterior legs. The basipodites are unarmed, and the 
ischiopodites are as short as these joints; the meropodites have 
a characteristic form. These joints appear suddenly enlarged 
at their under margins near the proximal fourth of their length, 
and then again gradually taper towards their distal ends; the 
breadth of the enlarged part amounts to a fourth of the whole 
length of the joint. The carpopodites, which are a little shorter 
than the meropodites, present the usual slender form; the 
slender propodites are a little shorter than the carpopodites, 
being slightly longer than half the length of the meropodites. 
The straight, thin, and acute dactylopodites are only half as long 
as the carpopodites. The legs of the fifth pair are a little 
longer than the peduncles of the external antenne; they are 
unarmed at their bases, like the legs of the fourth pair. The 
meropodites, which are slender and extend nearly as far 
forwards as the hepatic spine of the cephalothorax, present a 
peculiar notch or excavation near the proximal ends of their 
under margins ; this notch is surmounted by a singular, subacute, 
slightly curved, lamelliform prominence or tooth. A similar 
structure has been described by Mr. Spence Bate as being 
proper to the male of Peneus affinis, M.-Edw. (Spence. Bate, 
“On the Penzide,” ‘Annals and Magazine of Natural History,’ 
1881, vol. vii. p. 179), and, according to him, this peculiar notch 
is confined in that species to the ischium-joint of the fifth pair 
of legs, whereas in this species the meropodites are marked with 
