AMPHIBIANS. 79 



the back, which, however, do not form a continuous 

 band. Head dark velvety black. Devours lizards 

 and blindworms. The Blindworm (Anguis fragilis) 

 is indeed snake-like, or rather worm-like (Fig. 49), 

 but nevertheless belongs to the lizards, with which its' 

 internal structure agrees. 



CLASS IV. : AMPHIBIA (AMPHIBIANS). 



Cold-blooded Vertebrates (p. 19). The heart has 

 only one ventricle and two auricles (cp. p. 21). The skin 

 is naked, damp, usually slippery and smooth ; it helps 

 in respiration. Although several Amphibians resemble 

 various ReptOes in outward appearance (Newt and 



Fia. 50.— Great Crested Newt (^Triton cristatus) ; male above, female below. 



Lizard, Figs. 50 and 46), the structure of the skeleton 

 is quite diflFerent. Upon the whole, Amphibians 

 resemble fishes more closely, and they breathe by 

 gills when they are young, which strengthens the 

 agreement. They undergo a metamorphosis. The 

 just hatched young at first hold fast by suction to 

 the jelly of the spawn; they have external gills. They 



