CHAPTER II 



SKELETON OF URODELA AND ANURA SKIN COLOUR -CHANGING 



MECHANISM POISON -GLANDS SPINAL NERVES RESPIRA- 

 TORY ORGANS SUPPRESSION OF LUNGS URINO -GENITAL 



ORGANS FECUNDATION NURSING HABITS DEVELOPMENT 



AND METAMORPHOSIS 



SKELpyroN OF THE Urodela 



The vertebral column. — The number of vertebrae is smallest in 

 the terrestrial, greatest in the entirely aquatic forms, and is excep- 

 tionally large in the eel-shaped Amphncma. In the following- 

 table the sacral vertebra is included in those of the trunk. 



The vertebrae of the Urodela and those of the Apoda differ 

 from those of all the other Tetrapoda ^ by possessing no special 

 centra or bodies. That part which should correspond with the 

 centrum is formed either by the meeting and subsequent complete 

 co-ossification of the two chief dorsal and ventral pairs of arcualia 

 ^ Credner's term lor all Vertebrates higher than fishes. 



