NOTES ON THE HABITS AND DEVELOPMENT OF 

 THE FOUR-TOED SALAMANDER, HEMIDACTYLIUM 



SCUTATUM (SCHLEGEL) 



BY SHERMAN C. BISHOP 



The four-toed salamander, Hemidactylium scutatum 

 (Sclilegel) , although widely distributed has been considered uncom- 

 mon in almost every locality from which it has been recorded. So 

 little has been written concerning the habits of this species that 

 an account of the finding of the animal and its eggs in abundance 

 and a description of some of the stages of its development may 

 prove of interest and throw some light on questions involving meta- 

 morphosis and habits not heretofore answered. 



The genus Hemidactylitim, represented by the single known 

 species, is closely related to Plethodon from which it differs structu- 

 rally in the absence of the fifth toe on the hind foot and, in a slight 

 degree, in the number and arrangement of the teeth. If the deficiency 

 in digits be disregarded, there is no more diversity in the characters 

 of Hemidactylium and Plethodon than is found in members of the 

 genus Plethodon itself. From the genus Batrachoseps, after which 

 it is usually placed, it differs, according to Cope ('89), in having a 

 prefrontal bone. In common with other members of the family 

 Plethodontidae, the four-toed salamander is lungless. Of the several 

 species of Plethodon, it is most nearly related to P. cinereus, 

 both in structure and habits. Like that species, it has the tongue 

 attached medially in front with the side margins free; .but the 

 median line of attachment in H. scutatum is confined to the 

 anterior half, while in P . cinereus it is continued almost to 

 the posterior margin. 



Parasphenoid teeth in H. scutatum in two elongate areas 

 well separated; in P. cinereus these areas are almost con- 

 tiguous; vomero-palatine teeth in two crescent shaped patches and 

 more nimierous than in P. cinereus. Externally H . scu- 

 tatum differs markedly from P. cinereus in the color of 

 the head, trunk and under parts, in its less robust form, and by 

 having but four toes on the feet. 



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