1 88 PATTEN AND REDENBAUGH. 



The first haemal nerve, or lateral nerve (/.«.), follows the general course of the 

 lateral eye nerve, but continues posteriorly far back onto the neural side of the 

 abdomen. 



The haemal nerves of the hind-brain (/4.«.^) radiate from the brain to the 

 margins of the prosomatic carapace, and each one passes anterior to the append- 

 age of its own metamere. The integumentary portions divide into haemal and 

 neural branches of which the haemal branches (h.) are cut off. Each haemal 

 branch gives off a small nerve, which turns back toward the median line upon the 

 haemal side of the body. 



The haemal nerves (h.nJ ^^^ ^) of the accessory brain pass through the occipi- 

 tal ring and out to the sides of the body between the operculum and the sixth 

 thoracic appendage. The seventh innervates the posterior angles of the cephalo- 

 thorax, the eighth the opercular portion of the abdomen. 



The next five haemal nerves (/^.w.^-") arise from the five branchial neuromeres 

 and pass out anterior to the five pairs of gills to the sides of the abdominal cara- 

 pace and innervate the first five spines (a.j.'-'^) upon the sides of the abdomen. 



The first post-branchial nerve (h.n}'') innervates the last abdominal spine 

 (a.j.'*) ; the second post-branchial nerve (h.n}^) and one branch of the third post- 

 branchial (Ji.n}'') innervate the muscles of the telson and the posterior angles of 

 the abdomen ; and the caudal branch of the third post-branchial nerve innervates 

 the telson. 



Intestinal branches {/.«.'"''') arise from all the haemal nerves from the sixth to 

 the sixteenth and pass to the longitudinal abdominal muscles and to the intestine. 

 Those from the sixth and seventh neuromeres (/.«.* ^^^ ?) pass through foramina 

 in the endocranium. 



Cardiac nerves (s.c.n.^-^^) arise from all the haemal nerves from the sixth to the 

 thirteenth. Those which arise from the seventh and eighth neuromeres (t.n.7 ^"<i ^) 

 fuse together. Six of the cardiac nerves {s.c.n.^-^^) communicate with a lateral 

 nerve, which has been called the lateral sympathetic nerve {l.s.n). A branch {x.) 

 from the fifth haemal nerve (h.n.^) may also be a cardiac branch. 



The lateral sympathetic nerve {/.s.n.) innervates the branchio-thoracic muscles 

 (b.t.m.). It receives in each metamere, from the eighth to the fourteenth, a branch 

 from either the haemal or the cardiac nerve. 



Two post-cardiac nerves {s.c.n.^* ^""^ '5) arise from the first two post-branchial 

 nerves and pass to the haemal side of the body, where they anastomose with a 

 branch from the last cardiac nerve {s.c.n}^) and innervate the extensors {t.e.m.^) of 

 the telson, and the epidermis posterior to the heart. 



