METAMORPHOSIS OF AMPHIBIAN ORGANS 251 



lungs; soon after this they begin to float permanently on top of 

 the water and do not take food for several days. The gills and 

 fins start to reduce in size and then the animals suddenly shed 

 their skin and in the short space of a day or over night, the gills 

 are reduced to mere small filaments. If the animals are not 

 removed from the water at this moment they soon become stiff 

 from asphyxiation, but may recover if taken out before dead. 

 When removed from the water each animal was transferred into 

 a glass jar of the same size as those used for the larvae, but the 

 bottom of the jars was covered with a piece of moist filter paper 

 and a small amount of water. The jars were kept closed all 

 the time by means of plate-glass. In the following text this 

 condition will be called 'land-condition.' This equipment was 

 not changed until the beginning of 1917, when the filter paper 

 was replaced by gravel. 



As long as the animals were larval they were fed on Tubifex 

 thrown into the water. After metamorphosis earthworms were fed. 

 Though most of the animals after they had been metamorphosed 

 commenced to take readily pieces of earthworms from a pair of 

 forceps, they later on stopped doing this after they had been 

 neglected for some, time and had to be fed forcibly by stuffing 

 the pieces into their mouths. It appeared however, that this 

 method of artificial feeding was not satisfactory and many of 

 the animals were lost. It should be mentioned that by feeding 

 the animals regularly they easily learn to take even whole earth- 

 worms from the forceps and there is no difficulty in raising Sala- 

 manders to full size in this way as we have experienced in other 

 experiments. 



Forty-six larvae of Amblystoma punctatum were operated 

 upon in the manner described above, an odd number and the 

 consecutive even number making one pair X and Y, each of 

 which carried on one of its shoulders a piece of skin and one eye 

 taken from the head of a third animal A (fig. 1). The animals 

 used for these experiments hatched between the 3rd and 8th of 

 May, 1916 from eggs collected by Mr. R. Deckert of Bronx 

 Park in swamps near Whiteplains, N. Y., during the spring of 

 1916. All three individuals of one pair (A, X and Y) were 



