British Freshwater Entomostraca. aoe 
C. setosa is characterized by the presence of small spines 
all over the body, these spines springing from every node 
of the conspicuous reticulations of the shell and head. 
Lilljeborg states that, in the male, they do not arise from 
the nodes only, but I have not found any difference between 
the sexes in this respect. Similar spines are described in 
C. echinata, Moniez, and in C. acanthina, Ross, but in the 
former the postabdomen is even broader than that of 
Fig, I. 
Ceriodaphnia setosa. 
A. Ephippial female. 
B. Head of male. 
C. Fornix and margin of ephippium of female. 
D. Postabdomen of female. 
C. laticaudata, and in the latter the front of the head is 
said to be smooth, while the postabdominal claws are denti- 
culate. 
The ephippium is marked off from the valves by a 
broad, clear space which is free from reticulations, and 
the ephippium itself is covered with small reticulations, 
each with a small knob or boss in the centre, but with 
no spines. 
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