164 PATTEN AND REDENBAUGH. [Vol. XVI. 



passes haemally just anterior to the last entapophysis {enta/'f). 

 A branch is given to the lateral sympathetic before the post- 

 cardiac nerve separates from the main nerve. This is the 

 posterior limit of the lateral sympathetic (Text-fig. 18). Near 

 the entapophysis the post-cardiac nerve gives off branches to a 

 slip of the extensor muscle {t.e.m.") of the caudal spine, which 

 is attached to the last three entapophyses. In this muscle the 

 branches anastomose anteriorly with the corresponding branches 

 from the last branchial neuromere, and posteriorly with a simi- 

 lar branch from the second post-branchial neuromere. The post- 

 cardiac nerve terminates in the epidermis in the haemal median 

 line posterior to the heart. 



(c) Integumentary Branches. — The integumentary branch 

 passes diagonally backward to the thickened rim of the cara- 

 pace, where it gives off haemal and neural branches and some 

 small nerves posteriorly and anteriorly, but the main branch 

 supplies the last large spine (a.s/'f) upon the edge of the 

 carapace. 



(2) Nerves from Second Post-Branchial Neuromere. — This 

 pair of nerves {Ji.71.'^), because of their larger area of distribu- 

 tion, are somewhat larger than the preceding haemal nerves. 

 They arise from the terminal ganglionic mass just back of the 

 first post-branchial nerve, and pass posteriorly and outward 

 posterior to the last haemo-neural muscle {h.n.m.''*). This 

 nerve is also divisible into intestinal, post-cardiac, and integu- 

 mentary branches. 



(a) Intestinal Branches. — From the base of the nerve [i.n.^^) 

 a small fiber passes backward along the intestine to which it 

 gives off several branches. It then continues backward nearly 

 to the rectum, where it unites with a nerve {i.n.'^) from the 

 third post-branchial neuromere. No muscular branches have 

 been found. 



(b) Post-Cardiac Branch. — Posterior to the last haemo-neural 

 muscle a large branch goes haemally between the slips of the 

 flexors of the caudal spine. Near the haemal side of the body 

 this branch divides into two ; one going outward to the external 

 slips of the extensors (t.e.m..^) of the caudal spine, and to the 

 epidermis in the neighboring region ; the other going toward 



