152 



PATTEN AND REDENBAUGH. 



[Vol. XVI. 



and 9; Pis. VI-X, Figs. 1-3, 5, 11, and 12, s.c.nJ') is present 

 in the sixth neuromere only. It arises from the haemal 

 side of the haemal nerve {Ji.n.^), about midway between 

 the brain and the outer edge of the entocoxite. Where it 

 separates from the haemal nerve a small recurrent branch is 

 sometimes seen passing backward from the cardiac nerve to 

 the integumentary portion {in.n.) of the main nerve. It passes 



Fig. 13. — Diagram showing the distribution of the intestinal nerve of the second neuromere. The 

 left anterior comu of the endocranium with attached muscles, one of the aortic arches, and 

 the anterior portion of the brain are represented as seen from the median side. The fore-brain 

 and endocranium are cut in two in the middle line. 



a.cor., anterior comu of the endocranium ; ao.a., aortic arch; eiido., endocranium; h.c, 

 haemal side of carapace. 



Muscles : 2 a and b, plastro-coxal muscles inserted upon the anterior border of the ento- 

 coxite of the second appendage ; /./.w.a-c, tergo-proplastral muscles. 



Nerves : a.c, anterior commissure; br., fore-brain ; h.n.^, haemal nerve of second neuro- 

 mere; i.n.^, intestinal nerve of second neuromere ; l.e.n., lateral eye nerve ; m.ol.n., median 

 olfactory nerve; n.n.^, cheliceral nerve; o.c, portion of circum-oesophageal collar. 



haemally, outside of the branchio-thoracic muscles {b.t.vi.) and, 

 bending toward the anterior side, passes through the pericardium 

 to the inter-tergal muscle. Within this muscle its branches 

 anastomose with the cardiac branches of the next posterior 

 neuromere. 



Some of the branches supply the epidermis in the haemal 

 median line over the first pair of ostia (os!") of the heart, and, 

 although no connection has yet been found between these 



