334 Records of the Indian Museum. [Wire Vie 
ments are 15: 18: 16: 12. The penultimate joint bears a distal 
spinous process and the last joint terminates in two processes of 
unequal length. The right leg has only three segments and termi- 
nates in two short processes. 
These specimens very closely resemble P. aculeatus, especially 
as regards the spinulation of the legs, but they differ markedly in 
the length of the antennae and the structure of the 5th legs, and 
I conclude that they are a new species. 
NoTE.—Since the above was written, other examples of this 
species have been obtained at the mouth of the Tavoy River, and it 
would appear probable that it is a regular inhabitant of estuarine 
waters in this region. 
Genus Acrocalanus. 
Acrocalanus inermis, sp. nov. 
Pl. xvi, figs. I—9. 
As already mentioned a large number of specimens in various 
stages of development were obtained. As regards their general 
structure and appearance they agree very closely with other mem- 
bers of this genus; they have all five segments of the thorax 
separate ; the 5th pair of legs is practically absent in the female 
and only the left one present in the male. ‘They differ, however, 
in having no spines on the margins of the exopodite of any leg. 
I do not consider that this is sufficient ground for creating a new 
genus and propose to include this species under the name of 
A. inermis. 
Stage I. Unknown. 
Stage 2. 
2 Total length 1°08 mm. 
The head is separate from the 1st thoracic segment and ter- 
minates anteriorly, its bifid rostrum consisting of two sharply- 
pointed processes. The 4th and 5th thoracic segments are also 
separate and the posterior margin of the thorax is rounded and 
bears a row of small spines. 
The abdomen consists of four segments and is contained 3 times 
in the length of the cephalo-thorax ; the furcal rami are symmetri- 
cal and bear four terminal setae. The proportional lengths of the 
abdominal segments and furca are 24: 14: 11: 18: 12. 
The Ist antennae reach to the end of the furcal rami and con- 
sist of 23 separate joints; the rst and 2nd segments are com- 
pletely and the 8th and oth partially fused together. The relative 
proportions are as follows :— 
Segments—— 
1-2. 3.450.175 6-9. LO, 11. 12 13) 4 et 5 Ose ee oan: 920; 2.19 2m ee Anas 
35. 9-9: 9.9.10, 15. 8." 3So. 10. Tia ke LD ot 2) ao O75 oT ieen eS 
Each of the Ist six segments bears a transverse row of very 
small delicate spines. 
