1925] Storer: A Synopsis of the Amphibia of California 
139 
toes where likely to come into contact with the moist substratum either 
on the ground or in a cavity in a tree, and large size of maxillary and 
mandibular teeth placed at the margin of the jaws where most likely 
to be of service in offense or defense and where most serviceable in 
gnawing off fungus or enlarging the entrances, to cavities in rotted 
wood. The jaw teeth of Aneides are different in form and placement 
from those of other Plethodonts or other amphibia generally, and their 
semi-exposed location parallels the unobstructed placing of the incisor 
teeth of rodents. 
The period of egg deposition with Aneides coincides with the time 
of maximum summer heat and dryness and might be thought to indi- 
cate persistence of an ancestral summer-spawning period in the face 
of adverse climatic conditions. However, I believe a simpler and more 
logical explanation is possible. Since the adult (female) guards and 
probably supplies moisture to the eggs, the danger of desiccation is 
obviated. Emergence of the young at some time in the spring months, 
particularly if they happened to be born in a tree cavity, would leave 
ample opportunity for them to perish through desiccation. But with 
egg deposition in July or August, followed by a period of development 
lasting for about two months, the time of emergence of the young 
animals is at or after the advent of the first autumn rains. Thereafter 
the days are less hot, the ground retains its moisture more readily, 
young salamanders would be less likely to be killed by desiccation, and 
many species of insects would then be initiating their developmental 
cycle, affording stocks of larvae or soft bodied small-sized insects upon 
which the young salamanders might feed. Furthermore, dispersal 
from the parental tree cavity would be fraught with less danger 
during the rainy period than were it to occur at the beginning of the 
summer dry season. 
Whipple (1906a) has advanced the argument that the lungs of 
salamanders are chiefly hydrostatic in function, basing her contention 
on the fact that the aquatic urodeles living in relatively quiet water, 
possess a pre-pubic “ypsiloid” cartilage, which is of service in com- 
pressing the abdomen and hence the lungs, whereas the terrestrial 
species (Plethodontidae) lack this structure. More recently Wilder 
and Dunn (1920) have put forward the theory that the Pletho- 
dontidae originally were inhabitants of mountain brooks, and that the 
loss of lungs was due to lack of need for these organs in the habitat 
mentioned. The Appalachian Mountain region, which for a long 
geological period is believed to have afforded this habitat, is indicated 
