THE LIFE HISTORY OF DESMOGXATHUS FUSCA. 



INEZ WHIPPLE WILDER, 

 SMITH COLLEGE. 



Although Desmognathus fusca ranks as one of the commonest 

 of the American salamanders, at least in the eastern part of the 

 United States, our published accounts of its life history are 

 singularly meager and fragmentary. It is hoped, therefore, that 

 the following account, culled from observations extending through 

 several years during which this species has served as material 

 for class work in anatomy, histology, embryology, and physiology 

 in our laboratory courses at Smith College, as well as for several 

 lines of individual research, may prove of some interest and even 

 practical value to others who are engaged in the study of am- 

 phibian life. Incidentally, too, there is always the possibility 

 that facts presented for their intrinsic interest may prove to 

 have some broader biological significance, particularly in a field 

 like that presented by the amphibians, in which there are in- 

 volved, both phylogenetically and ontogenetically, so many 

 environmental transitions which call for adaptive response. 



SYSTEMATIC POSITION AND SPECIFIC CHARACTERS. 



Desmognathus jusca is a representative of the family Desmog- 

 nathidae, which, together with the family Plethodontidae com- 

 prises all of the American Urodeles now known to be lungless. 1 

 In common with the other members of these two families, 

 Desmognathus possesses the naso-labial groove (Whipple, 'o6a) 

 and lacks the ypsiloid cartilage (Whipple, '066). 



The following description of the external appearance of 

 DesmognatJnis fusca is given by Morse ('04, p. 115): " Desmog- 

 nathus fusca fusca Raf. Above dark, with a median dorsal band 

 of lighter generally brown in color and specked with black. 

 Below gray with black specks forming a marbling. . . . Very 

 variable in color. Costal grooves 14. Length 4^/2 inches." 



1 Amblystoma opacum, reported lungless by Lonnberg, has since been shown to 

 possess fully developed, functional lungs (Whipple, '066). 



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