THE EGGS AND YOUNG TADPOLES 23 



oxygcn-deficient and liighly polluted environment is produced. They 

 even come within some distance of having the gill modifications of the 

 more extraordinary animal, for they momentarily spread their gills 

 in the surface film. The change in habit needed to convert one type of 

 life liistory into the other seems to consist mainly in the building of the 

 waW, for the anatomical, physiological and psychological modifications 

 necessary for survival in a polluted environment are already j^resent. 

 When the mouth opens, the tadpoles enter another phase of their 

 lives, and this forms the subject of the next chapter. 



REFERENCES 



Balcells, E. (1956) P. Inst. Biol ApL, 24, 81-121. 



Bles, E.J. (1906) Trans, roy. soc. Edin., 41, 789-821. 



Cambar, R. (1953) C. R. Acad. Sci. Paris, 237, 4.355. 



DiCKERSON, M. (1906) The Frog Book (New York). 



Douglas, R. (1948) J. Anim. EcoL, 17, No. 2, 189-92 



FiscHER-SiGWART, H. (1897) Vjschr. naturf. Ges. Zurich, 238-316. 



Gayda (1921) Arch. FisioL, III, 211. 



Helff, O. M. and Stubblefield, K.J. (193 1) Physiol. ZooL, 4, 271-86. 



Krizenecky, J. and Podhradsky, J. (1924) Pfliig. Arch. ges. Physiol, 204, 471-6. 



Krogh, a. (193 i) Biol. Rev., 6, 412-42. 



Macfarlane, R. G. and Barnett, B. (1934) Lancet, 2, 985. 



Moore, J. A. (1939) Ecology, 20, 4, 459-78. 



Moore, J. A. (1940) Amer. Nat., 74, 89-93. 



Moore, J. A. (1951) Proc. Nat. Acad. Sci., 37, 862-6. 



Noble, G. K. (1926) Amer. Mus. Novit., No. 229, 1-7. 



Noble, G. K. (1927) Ann. NY. Acad. Sci., 30, 31-128. 



NussBAUM, M. (1897) Arch. mikr. Anat., 46, 479-500, 48, 545-50' 



RuGH, R. (1935)7. Exp. Zool., 71, 149-63. 



Savage, R. M. (1935) Proc. zool. Soc. Lond., 3, 605-10. 



Savage, R. M. (1937) Proc. zool. Soc. Lond., A, 3, 249-60. 



Savage, R. M. (1938) Proc. zool. Soc. Lond., A, 108, 465-80. 



Savage, R. M. (1950) Brit. J. Herpet., i, No. 3, 57-66. 



Seurat (1922) Bull. Soc. Nat. Alghie, 13, 45-60, 77-92, 109-140 (not seen). 



Spallanzani, L. Reference from Daudin, Histoire naturclle des Reptiles, An., 13, 



No. I, 233 (Dufart, Paris, ?i8o2). 

 SwAMMERDAM, J. The Generation of Frogs (English translation by Hill, 1758). 

 VoLPE, E. P. (1953) Physiol, zool, 26, 344-54- 

 WiTSCHi, E. (1952) Cancer Res., 12, No. 11, 763-86. 

 Wright, A. and Wright, A. A. (1949) Handbook of the Frogs and Toads of the 



United States and Canada (Comstock Publ. Co., Ithaca, N.Y.). 



