1 62 PATTEN AND REDENBAUGH. [Vol. XVI. 



branchial neuromeres is given off (Text-figs. i6 and i8; Pis. 

 VI, VIII, and IX, Figs, i, 3, 5, and 6, s.c.nP-'^) outside of the 

 branchio-thoracic muscles {b.t.m.) or tendinous stigmata {t.sP-'^), 

 and, after giving a recurrent branch to the lateral sympathetic 

 {l.s.n.), passes haemally, anterior to the entapophysis and poste- 

 rior to the branchio-cardiac canal {b.c.cP''^) of its own neuromere. 

 Having reached the haemal side of the animal, it turns toward the 

 median line, gives a recurrent branch anteriorly to the peri- 

 cardial nerve (/.«.), and breaks up into small branches which 

 ramify through the epidermis, haemal to the heart. Over each 

 pair of ostia {osS''^) of the heart a pair of these branches pass 

 down from the epidermis to the median nerve {iu.c.n.) of the 

 heart. 



The cardiac nerve {s.c.n.'^) of the fifth branchial neuromere 

 is a little different from the others. A portion of it some- 

 times separates from the haemal nerve far back near the base 

 of the latter, and follows it along to the lateral sympathetic, 

 where it receives another branch from the haemal nerve. This 

 latter branch, and not the main cardiac branch, gives the recur- 

 rent branch to the lateral sympathetic (Text-fig. 12). Near 

 the entapophysis (efita/-^) it gives a branch to the slip of the 

 extensor muscle {t.e.m.^) of the caudal spine, which is attached 

 to the last three entapophyses {enta/^''^). In this muscle it 

 anastomoses with branches from the post-cardiac nerves which 

 supply the same muscle. The connection of the cardiac branch 

 of this neuromere with the pericardiac nerve {p.n.) is also irregu- 

 lar ; sometimes this connection is entirely absent and some of 

 its branches pass backwards in the epidermis to the posterior 

 margin of the carapace. Whether these branches are prolonga- 

 tions of the pericardial nerve, or merely branches of the last 

 cardiac nerve, is difficult to say. 



(c) Integumentary Branches. — The lateral expansions of the 

 carapace are very thin just outside of the bases of the append- 

 ages, but very thick at the outer margins. The integumentary 

 branches, therefore, do not show a distinct division into haemal 

 and neural branches except at their distal ends. Near the 

 base of each appendage a small nerve is given off posteriorly 

 to the epidermis. The main integumentary branches (PL VI, 



