52 
L. Kaufman : 
change of gases is limited during larval life, for the blood of the 
pulmonary artery of amphibians before their metamorphosis is 
mostly arteric; the vessel is connected with the third branchial 
vein, containing blood oxygenated in the gills. Bataillon and 
others attribute to larval lungs the rôle of the air-bladder of fishes. 
According to Wintrebert, the lungs of tadpoles begin to act 
when gill-respiration becomes impossible: in water with adequate 
quantity of air, branchial respiration suffices for the interchange 
of gases; in dirty water tadpoles come to the surfaee and take air 
into their lungs. 
The structure of the lungs of the axolotl living in water and 
breathing by means of gills does not differ essentially from that 
of the lungs of terrestrial Amblystoma , where they discharge the 
function of respiratory organs. In both forms these organs are 
large and cylindrical, somewhat narrower at the ends. They attain 
the region of the animal’s hind limbs. The quantity of air is the 
same in the lungs of larvae and of full-grown specimens. In the 
histological structure, I was unable to notice any difference between 
aquatic and terrestrial forms. 
The gills, the fi n. 
Little attention seems to have been paid to this subject by 
authors working on resorption of the gills and the fin of amphibians. 
Loos and Barfurth studied the atrophy of the tail of tadpoles 
and they describe the changes occurring in the tissues of the tail 
during metamorphosis; but they do not consider what takes place 
in the gills at this stage. Only in Bataillon’s paper on the 
metamorphosis of Anura the degeneration of gills during metamor¬ 
phosis is discussed; he adduces some observations on the absorption 
of gills in Alytes. In the connective tissue of degenerating gills 
there appear many leucocytes containing products of histolysis. 
But these phagocytes do not restore all materials to the organism; 
the majority of gill-fragments, phagocytes and blood-cells fall out 
by the respiratory aperture. In the tail the blood-circulation ' is 
retarded. The atrophy of capillary vessels and the diapedesis of 
red and white blood-cells are phenomena of universal occurrence. 
As to the metamorphosis of the respiratory apparatus in Urodela 
no data seem to be known. Kornfeld studied the resorption of 
