NOTES ON THE GENUS MONSTRILLA. 577 
among Copepoda. The well-developed swimming feet, with 
their powerful musculature, and the equally powerful muscula- 
ture of the body, and, as Claparéde has pointed out, the total 
absence of hooks or limbs modified for grasping (excepting the 
antennz of the male, which have a merely sexual significance), 
speak against a parasitic habit. In the present state of our 
knowledge its mode of life must remain something of a mystery. 
Having no alimentary tract, and no organs for seizing or man- 
ducating food, it cannot feed itself. Possibly this creature 
may present an analogy with the Ephemeride, and the adult 
may be preceded by a predaceous larva supplied with mouth 
parts and an alimentary tract, which, after a succession of rapid 
ecdyses, develops into the mature sexual form, whose only 
function is that of reproduction. The fact that the female 
carries the ova would seem opposed to this view, but it might 
be suggested that the abortion of the muscles of the anterior 
part of the cephalothorax and the existence of numerous oil- 
globules in this region might afford, on the one hand, an 
economy in nutrition, and on the other hand a store of nutri- 
tive material sufficient to prolong her life for the period 
necessary for hatching the ova. It must be allowed, however, 
that the undoubtedly young specimens taken by Dr. Norman 
afford no support to this suggestion, except that in some of them 
rudiments of gnathites, which are entirely absent in the adults, 
are present. 
In concluding, I must express my great obligations to Dr. 
Norman for kindly lending me the specimens in his possession, 
and for procuring for me, from different sources, the other 
specimens which have enabled me to give an account of the 
species of this genus. 
