NATURAL HISTORY. 87 
number of segments, and is more gracefully 
tapered. The compound eye 1s embedded in the 
shell. The antenne are not composed of so 
many articulations as in the quadricornis, and the 
inferior pair of palpi are more plumose at their 
extremities. The most prominent distinction 
between the two species (independent of the 
difference in size, the present species being the 
smallest of the Cyclops), consists in this having 
a single branchial or respiratory organ under 
the rostrum ; it has also ten legs, and the female 
carries a single cluster of eggs under the abdo- 
men, somewhat resembling the wolf-spider. In 
some specimens which I have examined, the 
form of the respiratory organ was similar to that 
I have shown at figure 6. It is in constant 
motion, and produces a current in the water 
towards the animal. 
The legs, five only of which are seen in the 
side view, figure 5, are so accurately depicted 
that verbal description would be superfluous. 
The setaceous bristles forming the tail are not 
so numerous as in the quadricornis, but con- 
join with the body in producing the graceful 
figure it exhibits; while its intensely bright. 
colour serves to heighten the delight and grati- 
