THE RESPIRATORY SYSTEM OF AMPHIBIANS 



149 



III terrestrial aini)liil)iaiis, air is taken in thronj^;!! the nostrils with 

 the aid of nniseles of the mouth and throat, and passes into the two 

 internal sae-like diverticula of the pharynx, the lun<rs. (Fig. 91.) 



Epidermis 

 hromatophore 



Epidermis 

 Capillary— A 



a pillar 1/ 

 'onnective tissue 



Smooth muscle 



C hromatophore 

 Fig. 89 Fig. 90 



Fig. 89. — Diagram of the gill filament of Necturus. 

 Fig. 90. — Diagram of Neftunis gill filament more highly magnified. 



Floor of mouth 



r,, , . , I I longitudinal g^ 



Skeletal muscle < " p^ 



L cross v"r^^\ 



Connective tissue 



Cartilage {hyaline) MM^ 



Fig. 91.— Glottis, voeal cords and entrance to lungs of frog. 



In the water-dwelling forms the lungs are like the air sacs of the 

 fishes in their simplicity. (Fig. 92.) In the frog and other terrestrial 

 forms the internal surface is lined by simple squamous or cuboidal 



