156 PATTEN AND REDENBAUGH. [Vol. XVI. 



chial or abductor muscle {e.b.m.^) upon the posterior face of the 

 appendage ; the sensory branch innervates the epidermis of the 

 middle portion of the appendage. 



The third branch (i.oji.) is mainly sensory and innervates the 

 distal portions of the appendage. It also contains some motor 

 elements which supply the muscle strands {o.l.m. and i.l.m.), 

 moving the distal portions {o.l. and i.l.) of the appendage. 



(2) Haemal Nerves. — The haemal nerves (Text-figs. 14 and 

 15; Pis. VI-VIII and X, Figs. 1-3, 11, and 12, Jim? and h.n.^) 

 arise from haemal side of the brain and pass back through the 

 occipital ring and outward to the sides of the body, between 

 the sixth pair of legs and the operculum. The one belonging 

 to the chilarial neuromere arises outside of the opercular one 

 and turns outward anterior to the capsuliginous bar, while the 

 other one turns outward posterior to the bar. They are typical 

 haemal nerves and have the usual intestinal, cardiac, and integu- 

 mentary branches. 



(a) Intestinal Branches. — The intestinal branch {i.n.'') of the 

 chilarial haemal nerve is given off at the bend in the nerve 

 between the capsuliginous bar {b.c.'') and the base of the occip- 

 ital ring, and passes through a foramen (y.7) in the endo- 

 cranium to the longitudinal abdominal {l.a.m.) muscles and, like 

 the intestinal nerve of the sixth neuromere, communicates with 

 a plexus supplying these muscles and sends a branch to the 

 intestine. 



The intestinal branch (i.n.^) of the opercular haemal nerve is 

 also given off at the bend of the nerve posterior to the capsu- 

 liginous bar (b.c.''). It does not pass through the endocranium 

 but plunges directly into the abdominal muscles. Its distribu- 

 tion is similar to that of the preceding. It is a notable fact 

 that in many cases these intestinal branches have been seen to 

 arise from the haemal nerve by two roots. 



(b) Cardiac Brandies. — The cardiac branches {s.c.n.'^^'^^^) 

 of these two neuromeres arise from the haemal nerves at some 

 distance beyond the origins of the intestinal nerves, and fuse 

 together into one large nerve. The opercular root gives off a 

 branch to the lateral sympathetic (l.s.n.) which innervates the 

 branchio-thoracic muscles (b.t.m.). The fused cardiac nerve 



