Eoss Granville Harrison 



205 



they extend further from the medullary cord and finally terminate alto- 

 gether. Their exact mode of ending could not be determined. Distal 

 to the point of termination of these intrinsic fibers of the cord there are 

 no nerves of any description in the organism,^ except sometimes the r. 

 lateralis vagi, which, as has been shown, grows out from the vagus 

 ganglion/ a structure not affected by the operation. The sense organs of 

 the lateral line are also present in such cases. Spinal ganglia are, as would 



PAM- 



Fig. 7. Fig. 8. 



Fig. 7. Transversa section through the posterior part of the trunk of the specimen 

 shown in Fig-. 3; iiit, intestine; nc, notochord ; my, myotome; p. a. »n., primary abdominal 

 muscle ; r, rectum ; wd. Wolffian duct. X 50. 



Fig. 8. Trans\erse section through the tail of the specimen shown in Fig. 3. iny, myo- 

 tome ; nc, notochord. X 50. 



be expected, absent from the entire region distal to the cut end of the 

 medullary cord. In those cases in which the small dorsal strip containing 

 the spinal cord was not cut off, but left attached by its anterior end to the 

 head of the embryo, the longititdinal bundle fibers remain entirely within 

 the walls of the cord and no free nerve fibers whatever are to be found in 

 that part of the embryo where the immediate connection with the cord is 

 severed. 



^ Cf . Harrison, 03a. 



