AMPHIBIANS. 



17 



(tailed forms). In ideutil'viiig llie 8alienti;i the fulluwiiig char- 

 acters are used, — general external appearance, pi'oportionate length 

 of head and body, ])r()|)or1ionate length of hind limb and body, 

 presence or absence of ])arotid glands. ])resence or absence of lateral 

 glandnlar folds', teeth, presence or absence of disks on fingers and 



Fig. 1. Diagram of Mouth of Frog to Sliow Position of Teeth. 



n, Internal nares; v, Vomerine teeth; e. Eustachian tuUs; o, Oesophagus; (7, Glottis; 



t. Tongue, 



toes, gromid color and pattern. The characters used in the identi- 

 fication of the Caudata are, — general external appearance, propor- 

 tionate length of body and tail, shape of tail, nnmber of costal 

 grooves, number of toes on the hind feet, character and position of 

 teeth (Fig. 2), ground color and pattern. 



Fig. 2. Diagram of Mouth of Salamander to show Position of Teeth. 

 n, Internal nares; v, Vomerine teeth; p, Paresphenoid teetli; t, Tongue. 



Teachers mav outline laboratorv and field work from the follow- 



ing suggestions. Tlie collecting and identifying of s])ecies shouhl 



precede or go along with the study of habils. The sjning is the best 



time to observe the species in The field, for this is the breeding 



3 



