352 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



j). 2), in which the circulation is similar to that in the 

 coxal plates of the thorax. 



On the course of the efferent vessels of the thoracic 

 and abdominal appendages, in the basal joint of each leg, 

 lie a group of unicellular glands (PL III., fig. 1, gl.) 

 which are excretory in function. 



The blood is a clear, colourless liquid, iu which are 

 numerous large corpuscles about 0"03mm. in diameter, for 

 the most part in rapid motion, as well as a number of 

 orange or vermilion-coloured oil globules of varying sizes. 

 The corpuscles are granular with a clear nucleus and dark 

 nucleolus (PI. III., fig. 2) ; they show amoeboid movement, 

 and are somewhat pear-shaped when travelling rapidly, 

 but become round when at rest. When the creature has 

 been fed upon carmine for some days, the corpuscles 

 contain carmine granules. A number of these globules 

 are frequently to be seen more or less at rest, about the 

 excretory organ at the base of the second antenna. 



The circulation of the blood is partly vascular, partly 

 lacunar, and the blood itself is mixed, the difference in 

 purity between that in one part of the body and that in 

 another being very slight. The purest blood passes 

 through the anterior aorta to the brain and antennae, from 

 the heart, but even this cannot be regarded as pure, since 

 the efferent vessels which supply the pericardial cavity 

 return blood from the appendages as well as from the 

 respiratory organs. 



The Muscular System. 



The muscles moving the segments of the body and 

 the appendages can be seen, with their points of inser- 

 tion, through the transparent exoskeleton. In addition 

 to those of the alimentary canal (see above in the digas- 



