aothor's abstract op this paper issued 

 bt the bibliographic service, august 5 



THE RELATION OF THE PARS INTERMEDIA OF THE 

 HYPOPHYSIS TO PIGMENTATION CHANGES 

 IN ANURAN LARVAE 



W. W. SWINGLE 



Oshorn Zoological Laboratory, Yale University 



FOUR TEXT FIGURES AND TWO PLATES 



The experiments recorded here were begun by the writer in 

 April, 1920, at the Biological Laboratory of Princeton University 

 and some of the principal results mentioned in the present paper 

 were obtained at that time. The experiments were discontinued 

 during the summer to be resumed in September at this laboratory 

 on a much larger scale than was possible before. The earlier 

 experiments were confined to transplanting the anterior and in- 

 termediate lobes of the hypophysis of adult Rana catesbeiana into 

 immature larvae of the same species, i.e., the grafts were homo- 

 plastic. The pars nervosa and pars tuberalis of the gland were 

 not taken into consideration at that time. 



In the earlier work it was observed that transplantation of the 

 anterior lobe of the anuran hypophysis into year-old larvae aver- 

 aging 85 mm. total length induced a slight increase in the body 

 growth of the animals and marked acceleration of limb growth. 

 In two individuals the fore legs appeared, and there were other 

 evidences of metamorphic changes within thirty* days from the 

 date of engrafting the glandular tissue. The majority of the lar- 

 vae did not go so far as this before the experiments were aban- 

 doned. Transplants of the anterior lobe of pituitary were also 

 made on larvae averaging 50 mm. total length, without limbs. 

 The growth rate increased markedly in these younger animals, 

 and there was also rapid growth and differentiation of the hind 

 limbs though the metamorphic changes were not nearly so 

 marked nor so rapid as following transplantation of the pituitary 



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