294 



AMPHIBIA 



Respiratory System.— The most striking example of metamor- 

 phosis occurs in those amphibia in which the larval external and 

 internal gills are replaced in the adult by lungs (see Figures 158 and 

 159). In many salamanders, respiration is pharyngeal and cuta- 



Infernal carotid 



Hyoid 



—/famus 



cornmun/'cans 



— Oil I cleft 



■Occipifo-vertebral 

 — Bulbus arteriosus 

 ■Scapular 

 -Conus arteriosus ^ 



■Pulrnonory 



—Anterior scapular 



-y^ Broc/lio/ 



r^ Fhsterior scapular 



£piijastric 



Pancreot Ic — — 

 Hepatic — 



Anterior mesenteric — 



t/roqenifal — C 



liypoqastric 



■Dorsal aorta 

 ■Gastric 



Coelioco -mesenteric 



—Accessory mesenteric 



^ Posterior mesenteric 



L umbar 



■Posterior epiqosfric 



Iliac 



—Sciatic 



-Caudal 



Fig. 158. Arterial system, ventral view, of Cryptobranchus. (After Reese, Amer. 



Nat., 1906, vol. 40.) 



neous. 



Even in the frog, during hibernation, respiration is cuta- 

 neous. The body temperature of the frog varies from 58° to 61,° 

 Fahrenheit. Salamanders are mute, but frogs and toads are noisy 

 creatures, especially at spawning time. 



