ARBOREAL SALAMANDER. Aneides lugubris lugubris (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.—Recorded commonly in Transition Zone near McCarthy ranch, 3 miles east of Coulterville. Lives near or on damp ground within or under logs, under 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 in 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 contained remains of terrestrial beetles and large ants—the sort of food materials which is ground-dwelling, night-foraging amphibian might be expected to take.