240 THE ROYAL SOCIETY OF CANADA 



A is connected with the transverse nerve just before and after cross- 

 ing the tracheal trunk. In the back the nerve branches freely, the 

 branches going to the dorsal muscles and to the integument as in the 

 case of nerve A of the other abdominal ganglia. 



Nerve B arises ventrad of the origin of A, travels straight back 

 and then bends outwards so that the latter part of its course is obliquely 

 backwards. This nerve and its branches are confined to the ventral 

 and lateral portions of the seventh segment, and as their distribution 

 does not differ markedly from that of nerve B of the first segment, 

 it is unnecessary to describe it in detail here. 



Nerve C originates at the lateral side of the posterior end of 

 the ganglion and runs backward unbranched until it enters the eighth 

 segment. Here it gives off two stout nerves a and b from its inner side, 

 these supply the longitudinal muscles of the anal segment. The third 

 branch c also goes to the anal muscles. Branches d and e inner- 

 vate the dorsal wall and the nerve finally goes to the terminal spiracle. 



Nerve D. This nerve almost invariably arises in connection 

 with nerve C and the two nerves coalesce throughout part of their 

 course. The length of the coalesced portion varies considerably with 

 different specimens. In a few of the specimens examined nerve D 

 arose ventrad of the origin of C and the two nerves continued free 

 throughout their course. In one case the nerves on one side of the 

 ganglion were free and those on the other side united. 



Nerve D travels backward above the ventral recti muscles un- 

 branched until it enters the last segment; then it passes beneath the 

 ventral recti muscles of this segment and divides into four branches 

 which innervate the ventral wall. 



Nerve E originates from the ventral side of the posterior end of the 

 ganglion near the median line. It runs back into the last segment. 

 The proximal branch, (figs. 1, 5, and 7, i.n.) is the intestinal nerve, 

 It travels to the side of the intestine near the junction of the rectum 

 and colon and then bifurcates. Both branches again fork. The 

 anterior branch (fig. 7, a) sends one branch forward parallel to the 

 lateral margin of the intestine. This branch gives off several nerves 

 which innervate the. longitudinal and circular intestinal muscles. It 

 has been traced as far forward as the anterior end of the ileum where 

 it sends a nerve to the bladder-like expansion of the base of the 

 Malphigian tubule. The second branch of a runs back innervating 

 the rectum and the posterior portions of the Malpighian tubules. 

 Branch b also divides into two nerves; one of these runs forward, 

 sends a cross-nerve to branch a and then goes to the ventral portion 

 of the colon; the other innervates the ventral side of the rectum. 



