Description of Plate 6. 



Lung of Necturus mi l ,us. 



Fig. 9. Surface view of elastic fibers over the pulmonary artery. 

 Orcein staining, x 400. 



Fig. 10. The finer network of nerve fibers, showing meclullated 

 and non-medullated fibers and nerve cells. Methy- 

 lene blue, x 75. 



