102 
a high power, they are found to be subspherical, granular, 
and of various shades of greenish yellow colour. Some 
of the cells exhibit faint amceboid movement. It 1s pro- 
bable, therefore, that the digestion is intracellular. 
The food of these parasites is undoubtedly blood which 
we find in the alimentary canal, but whether the absence 
of digestive glands in the adult accounts for its unchanged 
appearance has not been ascertained. In the young, 
where there is an apparent digestive gland, the contents 
of the alimentary canal are not red. 
CIRCULATION AND RESPIRATION. 
There is no heart or vascular system, and in the adult 
no movement of fluids could be observed which would 
indicate a blood circulation. The animal is probably 
dependent upon the blood sucked from its host for the 
supply of oxygen necessary to maintain hfe. It is there- 
fore possible that the early death after removal from the 
fish is due largely to the inability to take up oxygen from 
the water. The blood circulation could not be satisfac- 
torily traced in the cyclops stage. 
THE MuscuLar SYSTEM. 
The muscular system in the cyclops stage, although not 
so highly developed, is practically similar to that of 
Lepeophtheirus. In the adult female it is simply a net- 
work between the integument and the alimentary canal 
forming a supporting medium for the latter. 
THE NERVOUS SYSTEM. 
In the cyclops stage the central nervous system is the 
same as in the adult Lepeophthetrus. The nerves supply- 
ing the various appendages have also the same origin and 
direction as described in that type. The nerves marked 
4a, 4b, and 5a in Plate IIL., fig. 2, could not be traced. 
