CHAPTER II 



SKELETON OF URODELA AND ANURA SKIN COLOUR -CHANGING 



MECHANISM POISON - GLANDS SPINAL NERVES RESPIRA- 

 TORY ORGANS SUPPRESSION OF LUNGS URINO - GENITAL 



ORGAN S FECUNDATION NURSING HABITS DE VELOPMENT 



AND METAMORPHOSIS 



SKELETON 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 Amphiuma. In the following 

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



Trunk. Tail. 



Siren lacertina . . .22 35 + 



Necturus maculatus . .19 29 



Proteus anguinus 30 28 + 



Cryptobranchus alleghaniensis 20 or 21 24 + 

 0. scheuchzeri . . .21 



G. japonicus . . . -2-2 22 to 26 



Amphiuma means . . 63 35 + 



Amblystoma tigrinum . 17 or 16 32 + 



Salamandra maculosa 17 27 



Triton cristatus ... 17 36 



Triton taeniatus . . . 14 or 15 36 + 



Triton palmatus . . .14 23 to 25 



Salamandrina perspicillata . 15 32 to 42 



Spelerpes fuscus ... 16 23 



The vertebrae of the Urodela and those of the Apoda differ 

 from those of all the other Tetrapoda 1 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 

 1 Credner's term for all Vertebrates higher than fishes. 



