90 



THE COCKROACH : 



is distinguished by the elongate nuclei of its constituent cells.* 

 Tracheal trunks pass to each ganglion, and break up upon and 

 within it into a multitude of fine branches. 



Fig. 41. Transverse section of Third Thoracic Ganglion, neu, neurilemmar cells ; 

 gc, ganglionic cells ; tr, tracheal tubes ; A, ganglionic cells, highly magnified. 

 X 75. 



n 



n e u 



Fig. 42. Longitudinal vertical section of Third Thoracic Ganglion, n, connective. 



The other references as in fig. 41. X 75. 



Bundles of commissural fibres pass from the ganglion cells of 

 one side of the cord to the peripheral nerves of the other. 

 There are also longitudinal bands which blend to form the 

 connectives, and send bundles into the peripheral nerves. Of 



* We have not been able to distinguish in the adult Cockroach the double layer of 

 neurilemmar cells noticed by Leydig and Michels in various Coleoptera. 



