On Amphibian Metamorphosis and Internal Secretions. 53 



substance of the prostate and pituitary anterior lobe, is without any effect in 

 relation to the metamorphosis of the Axolotl. 



6. Thyroid-feeding continued for 7 months was not accompanied by any 

 noteworthy somatic changes in Necturus. 



B. Pigmental Responses. 



7. Pituitary feeding (posterior lobe or whole gland) produces a marked 

 temporary dilatation, followed later by excessive contraction, of the dermal 

 melanophores in albino Axolotls. 



8. Adrenal medulla extract produces temporarily complete contraction of 

 the dermal melanophores in the Axolotl. 



9. Pineal administration (as extract or as food) rapidly brings about a 

 striking transient contraction of the dermal melanophores in frog tadpoles : 

 McCord and F. Allen's observations in this connection are fully confirmed. 

 It has, however, no effect upon the melanophores of the Axolotl. 



LITEEATUBE. 



Allen, B., ' Science,' 1920. 



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Boulenger, ' Proc. Zool. Soc.,' 1913. 



Von Chauvin, ' Zeit. f. Wiss. Zool.,' vol. 27 (1877), and vol. 41 (1885). 

 Detwiler, 'J. Exptl. Zool.,' vol. 31 (1920), especially pp. 149-151. 

 Emerson, 1 Proc. Boston Soc. Nat. Hist.,' vol. 32 (1905). 

 Fuchs, ' Biol. Centralbl.,' vol. 26 (1906). 



Gadow, H., " Amphibia and Eeptiles," ' Cambridge Nat. Hist.,' vol. 8 (1901). 



Gudernatsch, ' Am. Journ. Anat.,' vol. 15 (1914). 



Jensen, ' Meddelelser f. d. Kgl. Veter. og. Landb.,' vol. 44 (1916). 



Laufberger (in Czech), ' Biologicke Listy ' (1913). 



Laurens, 'J. Exptl. Zool.,' vol. 23 (1917). 



Leydig, E., ' Anatomisch-histologische Untersuchungen iiber Fische und Eeptilien ' 



(Berlin, 1853). 

 McCord and F. Allen, 'J. Exptl. Zool.,' vol. 23 (1917). 

 Piatt, ' Anat. Anzeiger' (1896). 



Schafer, ' Lane Medical Lectures ' (1913), California. 

 Smith, P. E., ' Amer. Anat. Mem.,' vol. 11 (1920). 

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 Swingle, 'J. Exptl. Zool.,' vol. 34 (1921). 

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