TADPOLES. 



99 



XIII. Tadpoles. 



The term tadpole is restricted to the developmental 

 stages between the formation of the spiraculum and 

 the egress of the fore limbs, and corresponds to the 

 second and third periods of Duges. Descriptions are 

 preferably drawn up from specimens in the third 

 period, which begins with the budding of the hind 

 limbs. 



Form. — The head and body are so fused that it is 



Fig. 42. 



■■-l.o. 



■m. 



m- 



Open moutli of — A. Pelodytes punctatus. b. Alytes ohstetricans. 

 b.o. Buccal orifice, l.p. Labial papillae, m. Mandibles, t. 

 Series of labial teeth. (Prom ' P. Z. S.,' 1891.) 



