CRANIAL NERVES OF CAECILIANS 551 



part of the dorsal musculature, and, turning around the pos- 

 terior border of the tendon of origin of the serratus muscle, 

 runs abruptly anteriorly and laterally until it reaches the pos- 

 terior end of the second sympathetic ganglion. Here it receives 

 a small gi'oup of motor fibers from the second spinal nerve, as 

 noted above, and then turns abruptly posterolaterally and ven- 

 trally. A short distance posterior to the second sympathetic 

 ganglion it gives off the second spinal fibers with some others, 

 which fuse with another second spinal twig, as previously no- 

 ticed, to form a nerve supplying the serratus muscle {sp.2 + 

 Svm.). The remaining motor fibers form a larger nerve that 

 supplies the lateral portion of the rectus abdominis musculature 

 (sp. Svm.). The main ramus, now wholly sensory (sp.Svc), 

 curves anteriorly around to the ventral side of the body and 

 passes out between the ventral rectus abdominis and sphincter 

 colli muscles, and finally through the latter to be distributed to 

 the ventral and lateral skin somewhat posterior to the corre- 

 sponding branch of the second spinal nerve. 



Fischer represents four main branches of the third spinal nerve 

 in Siphonops: 1) a communicating branch with the sympathetic 

 ganglion; 2) an anteroventrally directed branch, which is plainly 

 the sensory branch described above in Herpele (sp.Svc.) ; 3) 

 a ventral posterior branch, which corresponds to the motor 

 branch supplying the lateral rectus abdominis musculature in 

 Herpele {sp.Svm.) ; 4) a so-called lateralis, which is beyond ques- 

 tion the motor branch in Herpele that supplies the rectus sub- 

 vertebr^lis musculature {sp.Svmsv.). Wiedersheim recognizes, in 

 both the second and third spinal nerves of Ichthyophis, a large 

 motor branch to the rectus subvertebralis muscles, which condi- 

 tion the writer finds in the larval stage. Marcus finds a similar 

 branch of the third spinal in Hypogeophis, but designates it as a 

 ramus lateralis profundus. In Geotrypetes the writer finds cor- 

 responding branches on the first three spinal nerves. 



