Descelption of Plate 8. 



Leng of Necturus maculatus. 



Figs. 13 and 14. These section? show, the relative thickness of 

 the layer of muscle fibers, both internal and external 

 to the artery and vein. ISTote the superficial situa- 

 tion of both vessels, x 40. 



Fig. 15. The distribution of the main nerve trunks, x 3. 



