ON SOME AUSTRALIAN CLADOCERA. 467 
The reticulation of the carapace is not very distinct. The 
free edges of the valves are minutely denticulate. The eye 
is large with conspicuous crystalline lenses. The ocellus 
is very small, subrectangular. The antennules are short 
and somewhat rectangular, each has a spine at the edge 
and is tipped with a bundle of bristles. 
The tail-piece (fig. 2) is strongly built, and its posterior 
edge is fairly straight. There are ten spines on the infra- 
anal margin; these are strong and curved, but the tenth 
is very small. The end claws are long and curved. Hach 
bears a row of small spinules along its whole length; no 
secondary denticles are present at their base. The caudal 
sete are long and feathered anteriorly. There are three 
feathered spines on the supra-anal prominence, and two on 
the posterior. As many as Six summer eggs may be present. 
There is one winter egg in the ephippium. 
This species.somewhat resembles Ceriodaphnia reticu- 
lata Jurine. In general shape, the head is more erect and 
the posterior prominence more distinct and pointed in C. 
spinata. It also differs in the presence of denticles on the 
margin of the carapace, a greater number of anal spines 
and the row of tiny spinules along the whole length of the 
end-claws instead of the row of seven spinules near the 
base as in C. reticulata. 
Specific Characters.—Carapace, seen laterally, rounded 
oval in outline, with the posterior prominence above the 
middle axis of the body, very distinct. Head not very much 
depressed. Surface of the carapace not distinctly reticu- 
' lated; margins minutely denticulate. Hye large, ocellus 
very small. Antennules rectangular, each with a spine 
and a bundle of bristles. Tail-piece strong, ten infra-anal 
spines present; end-claws with a row of small spinules. 
Average length i°2 mm. 
Locality —Corowa, collected in March. Type specimen 
in the Australian Museum, No. P 4327. 
