158 THE SALAMANDER 



of the next transverse process. Here it turns sharply dorsally again 

 and passes between the MM. interspinals and dorsalis trunci 

 to supply the skin of the back. During its course parallel with 

 the vertebra it gives off one or two twigs to the above-named 

 muscles. This nerve would appear to correspond with the R. cutaneus 

 dorsi medialis (n.cut.d.m.) of Gaupp (Frog), carrying with it some 

 motor-fibres. 



Another cutaneous branch, rather smaller than the previous one, 

 and evidently representing the R. cutaneus dorsi lateralis (n.cut.d.l.) 

 of Gaupp (Frog), emerges from the lateral aspect of the ganglion. 

 Then, passing towards the transverse process, it penetrates the tough 

 connective tissue surrounding the bone and myosepta of the M. 

 dorsalis trunci, and supplies the overlying skin. There are also 

 two small muscular branches leaving the lateral aspect of the gang- 

 lion, one turning dorsally into the main portion of the M. dors, 

 trunci, and the other passing into the intertransversarius portion of 

 the same muscle. 



R. ventralis. This ramus is considerably larger than the ramus 

 dorsalis and forms the main portion of the nerve. It leaves the ven- 

 tro-lateral aspect of the ganglion, and, as its name implies, is distri- 

 buted to the muscles and skin of the ventral body-wall. It passes for 

 a short distance through the sub-vertebral muscles and supplies them 

 with fibres, then immediately after, or just before emerging from 

 them ventrally, it gives off the R. communicans ad sympatheticus. The 

 nerve then passes around the body-wall between the peritoneum 

 and the muscles, giving off a cutaneous branch about midway — 

 the R. cutaneus abdominis lateralis (n.cut.ab.L). It then supplies 

 several twigs to the MM. obliquus externus superficialis and 

 profundus, and to the ventral portion of the M. transversarius 

 s. obliquus internus. 



At the lateral edge of the M. rectus abdominis profundus it sends 

 a branch to the muscle (r.ab."), and then divides into muscular and 

 cutaneous branches. The former (r.ab.') passes deep to the muscle 

 and supplies the M. rectus abdominis superior, while the latter 

 becomes superficial and supplies the skin over the belly — R. cutaneus 

 abdominis medialis (n.cut.ab.m.). 



The exceptions to the general plan exemplified by the tenth spinal 

 nerve described above will now be considered individually and in 

 detail. They may be summarized briefly: 



The first spinal nerve has no dorsal root and only exceptionally 

 a ganglion in the adult. There is no dorsal cutaneous branch and 

 the ventral ramus supplies the tongue muscles. 



