SALAMANDEBS 653 



Arboreal Salamander. Aneides lugubris lugnbris (Hallowell) 



Field characters. — Total length 6 inches or less. Head wedge-shaped, with bulging 

 muscles above and behind eye; teeth on margin of upper jaw prominent; thirteen cross- 

 wise furrows (costal grooves) in skin on side of body between fore and hind leg; skin 

 everywhere smooth and soft. Upper surface dark brown, usually with small round spots 

 of yellow; under surface plain yellow. 



Occurrence. — Eecorded commonly in Transition Zone near McCarthy ranch, 3 miles 

 east of Coulterville. Lives near or on damp ground within or under logs, amder stones, 

 and in old wood rats' nests. Usually solitary. 



The Arboreal Salamander, in the Yosemite region, was found by us 

 only on or close to the surface of the ground. Elsewhere in its range the 

 species is known to inhabit damp cavities in oak trees. In the Sierras 

 we found it at but the one locality mentioned above, chiefly beneath logs 

 and stones in pastures and woodlands. Two adults were found iii the 

 interior of a charred and slightly decayed yellow pine log which was lying 

 on a sun-baked manzanita-covered hillside at the margin of the yellow 

 pine forest ; one of the animals was found in the nest of a wood rat ; and 

 another was discovered in a gopher burrow in the ground beneath a wood 

 rat's house. 



This species, like the Mount Lyell and Slender salamanders, is without 

 either lungs or gills in the adult condition. The animal is provided with 

 a moist skin which serves importantly for the interchange of oxygen and 

 carbon dioxide in respiration. Hence the animal keeps to humid situations, 

 where its soft skin can be kept from drying out. 



So far as known the Arboreal Salamander is active only at night and 

 spends the day hidden in some retreat of the sort mentioned above. During 

 the night the atmosphere is more humid ; hence the animals can venture 

 abroad then without danger of desiccation. 



The breeding season of this species is in late July and August. A 

 female salamander collected on June 3 contained eggs which were well 

 formed. 



The stomach contents of such of these animals as, were examined con- 

 tained remains of terrestrial beetles and large ants — the sort of food 

 materials which a ground-dwelling, night-foraging amphibian might be 

 expected to take. 



