New Crustacea from tiie Swan River Estuary. 
:i9 
The third urosome segment of imparipes is relatively short compared 
with that of inermis , resembling gracilis in this respect. It differs from 
gracilis and agrees with inermis , however, in being without most of the 
armature on the urosome and last thoracic segment figured for gracilis. 
Males : The structure of the fifth legs of the male differs from all other 
species by the hooked projection or spine coming from the middle segment, 
of the right endopod. The two subsidiary spines on the terminal segment 
of the right exopod are stronger than in other species. As figured for 
inermis and spin os us this segment bears only one subsidiary spine in the 
case of the former (externally), and none in the latter. However, as Dakin 
and Colefax point out for hrevicornis, Henry’s drawings and descriptions 
are sometimes incomplete, so they may be in the case of spinosus. The 
distal inner bulge of the terminal segment of the left exopod is not shown 
elsewhere except for a trace in sub solaria. 
The spur on the end segment on the left second endopod points towards 
the base in imparipes and inermis, but the adjacent setae have not become 
spinose in imparipes as in inermis, though they are shorter and less densely 
ciliated than in gracilis. 
KEY TO THE MALES. 
(Adapted from Nicholls). 
1. Both rami of left fifth leg 3-segmented 
Both rami of left fifth leg 2 -segmented 
Exopod 2-segmented, endopod 1-segmented 
2. Middle segment right fifth endopod with spine 
Middle segment fifth endopod without spine 
3. End segment of left second endopod armed with spur 
at right angles to axis and 7 setae 
End segment of left second endopod armed with spur 
directed to base, 2 spines, 5 setae 
4. Right fifth endopod 3-segmented 
Right fifth endopod 2-segmented 
spinosus Henry 
o 
impaixpes sp nov 
3 
gracilis Kiefer 
inermis Nicholls 
sub solaria 
Percival. 
hrevicornis 
Henry. 
Distribution of the Genus: Henry described hrevicornis and spinosus 
from fresh water in New r South Wales. Dakin and Colefax record brevi- 
cor^is as common in the New South Wales coastal lakes and record a single 
specimen from Port Jackson; gracilis and subsalaria occur in fresh to 
brackish water in New Zealand; inermis at the head of Spencer Gulf. The 
present species imparipes was taken in the Swan Estuary, W.A. 
LITERATURE CONSULTED FOR GLADIOFEREN S. 
Dakin. W. J. and Colefax, A. N., 1940: Plankton of Australian Coastal Waters 
off New South Wales. Pub. TJniv. Sydney Dep. Zool. Mon. 1. 
Henry, M., 1910: Some Australian Freshwater Copepoda and Ostracoda. Jour. 
Roy, Soc. N.S.W., LIII, pp. 29-48. 
Henry M., 1922': Fre«hwat°r Entomostraca of New South Wales, ii, Copepoda. 
Vr^o, Linn. S^c. N.S.W . , Vol. 47, pp. 551-570. 
Ki r f r. F Y.j "* 931 : Neuseelandische Susswassercopcpoden. Zool. Anz. 96, pp. 
278-282. 
a io 4 d. TlUornl Copepoda from South Australia, (II). Ucc. South 
VoL 8. No. 1, pp. 1-62. 
