GENEKAL FEATURES OF THE EARLY DEVELOPMENT 



■ OF desmog:nathus FUSCA. 



WILLIAM A. HILTON. 



This small salamander is very plentiful in eastern United States 

 and in many places is without doubt the most abundant of the Uro- 

 dela. It seems to be entirely nocturnal in its habits, venturing out 

 from hiding only at night. During the day time it may be found under 

 logs or stones on the edges of brooks, where it is neither very wet 

 nor entirely dry. This species is seldom found in water, almost never 

 in deep pools, although individuals may take to deeper water than 

 usual when trying to avoid capture. In general this form may be 

 said to be more aquatic than Plethodon cinereus and less so than 

 Spelerpes bilineatus with which it is often associated. The 

 egg-laying of the three species seems to be quite typical of the 

 average habits of the three animals so far as water is concerned. 

 The eggs of Spelerpes are laid in shallow water, those of Desmog- 

 nathus in damp places near small brooks or springs, while the eggs 

 of Plethodon are laid in a way similar to those of Desmognathus 

 but farther from water. The larval history of the three species also 

 illustrates the various degrees of aquatic adaptation. The larvae of 

 Spelerpes remain in water until they have attained a size nearly or 

 quite equal to that of the adult before losing their external gills, 

 that is, they retain their larval characters for a long time. The 

 larvae of Desmogiiathus live in water for only a short time ; they lose 

 their gills when very small. The young of Plethodon have a still, 

 shorter larval period, the gills are soon lost and the adult form is 

 attained without entering the water. 



The JoiRNAt. OF Morphology. — Vol. XX, No. 4. 



