300 



Mr. J. A. Dell on the Structure 



vermiform movements of the animal 

 there is a considerable amount of 

 sliding of the alimentary canal and 

 body-wall on one another, and a tight 

 commissure would be liable to be 

 snapped, or to tear the tissues. In 

 each segment, besides the commissures, 

 there is found a lateral branch running 

 downward and forward, and soon 

 splitting into three. Of these three 

 each posterior branch unites with the 



Fig. 5 ( x 20). 



Anterior part of tracheal system of larva, 

 in side view. 



Fro. 4 ( x 20). 

 Tracheal system of larva. 



anterior branch of the segment behind, 

 thus forming a loop, while the middle 

 branch breaks up into branches of 

 distribution. In the last segment, 

 immediately dorsal to the hinder part 

 of the heart, there arise from each 



Fig. 6 ( x 100). 

 Posterior spiracles of larvs. 



