1 68 PATTEN AND REDENBAUGH. [Vol. XVI. 



of a single nerve trunk lying, for the most part, neural to, or 

 outside of, the tendinous stigmata (t.s.^-'^). 



The branchio-thoracic muscles do not extend back as far as 

 the lateral sympathetic nerve goes, but their posterior portions 

 are replaced by the tendinous stigmata, which are segmen- 

 tal invaginations of the chitin furnishing attachment for the 

 branchio-thoracic muscles. The tendinous stigmata, six in 

 number, occur just posterior to each of the abdominal append- 

 ages ; i.e., from the eighth to the thirteenth metameres, inclu- 

 sive. The branchio-thoracic muscles, which are attached to 

 these stigmata, belong, then, in the eighth to thirteenth meta- 

 meres, and should receive their nerve supply from the eighth 

 to thirteenth neuromeres. This is actually the case ; the lat- 

 eral sympathetic nerve, or more properly the branchio-thoracic 

 nerve, receives a recurrent branch from each of the haemal 

 nerves from the eighth to thirteenth (Ji.n.^''^) ; but it also 

 receives one, a very fine one, from the fourteenth haemal nerve. 

 This would indicate that there is a branchio-thoracic muscle 

 belonging to the fourteenth metamere, which is very probable, 

 inasmuch as we have a pair of entapophyses, a pair of haemo- 

 neural muscles, and a pair of typical haemal nerves in this 

 metamere, but no appendage or neural nerves. 



The recurrent branches of the lateral sympathetic arise from 

 the haemal nerves near the segmental cardiac nerves {s.c.n.^~'*), 

 or from the roots of the cardiac nerves themselves. The 

 exact mode of origin varies considerably in different individuals ; 

 Fig. 1 8 (text) shows the relation of the lateral sympathetic to 

 the haemal nerves in one specimen. 



The cardiac nerves {s-cn.^^"^^^) from the seventh and eighth 

 haemal nerves fuse together, and the root of the eighth cardiac 

 nerve gives off a branch to the sympathetic. 



The root of the ninth cardiac nerve (s.c.n.^) also sends a 

 branch to the sympathetic. 



In the tenth neuromere the roots of the cardiac {s.c.n.^°) and 

 recurrent branches are flattened out, and some small nerves 

 are given off to the inter-entapophysial muscles. The origin of 

 the recurrent branch is, however, essentially the same as in the 

 preceding neuromere, except that the cardiac nerve does not 



