104 



INTRODUCTION. 



as regards their degree of development in individuals 

 of the same species, and their arrangement also varies, 

 within certain limits, irrespective of the species. I 



Fig. 46. 



Tadpoles showing sensory canals. A. Rana arjilis. B. Pelodytes 

 pundatus. c. Alytes obstetricans. (From ' P. Z. S.,' 1891.) 



have found them usually most distinct in Pelodytes, 

 Pchihiites cuUripes, Bana agilis, B. latastii, and Bom- 

 hinator igneus ; least in Bufo. I append figures (Fio-. 

 46) of tadpoles of Bana agilis, Pelodytes punctatus, 



