36 



S üb f am. 3 Plethodontinae: Spelerpesfuscus^ 



Manculus quadridigitatus , 



Subfam. 4 Desmognathinae: Desmognathus ochrophaetts, 



Desmognathus fuscus, 

 Desmognathus f. auriculatus. 



When we find that comparatively so many (10) and (6 genera) 

 different forms have been transformed in such a retrograde direction 

 to make the lungs more or less superfluous for the respiration , there 

 is no doubt that in the future this list of forms will rapidly increase 

 and that not only more species of the same genera , but also other 

 genera will be added. 



It seems rather early as yet to try to explain how and why these 

 animals have lost or reduced their lungs as neither the ontogenetic 

 development nor the anatomy, especiall^rithe circulatory system is 

 sufficiently studied, but it may have happened in this way. When 

 the animals lost the gills and increased in bulk the small and not very 

 composite lungs were insufficient for the respiration, so that the bucco- 

 pharyngeal cavity (? together with the exterior integument) even from 

 the beginning had to play a certain part. In some of the forms the 

 respiratory capacity of that cavity then increased more rapidly than 

 that of the lungs which is the easier to understand as the air breathed 

 first must pass through that cavity and because it is rather large in 

 these animals. When this capacity had developed to a certain extent 

 the lungs were not at all needed and thus without loss could and must 

 be reduced as superfluous, not. used organs. — It seems probable that 

 the development has taken this or at least a similar course as it is more 

 than difficult to believe that fully developed lungs, which completely 

 performed the respiration, could have been reduced. 



All these Salamandridae which I have examined lead a more or 

 less terrestrial life. Desmognathus fuscus auriculatus I found under 

 boards, logs and similar objects in muddy and moist places; but never 

 actually in the water >^. Manculus quadridigitatus lived hidden under 

 similar objects as the foregoing at the borders of the small lakes of 

 Florida, hut I never saw it in the water. Plethodon glutinosus I did 

 not catch myself but the food I have found in its stomach, various in- 

 sects (as beetles, ants etc.) earthworms, indicates a terrestrial life and 

 Cope says in »The Batrachia of North America«, p. 142, about this 

 species: »This salamander is entirely terrestrial in its habits«. About 



3 Professor Cope however says: »this species lives chiefly among the stones in 

 the many shallow rivulets and springs« etc. but also that it burrows »among stones 

 and in earth« and that the eggs are concealed »in a comparatively dry spot«. 



