430 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1959 
in flowing water. These cases are mostly found in small brooks, 
especially near their source, where spring water seeps out of the 
ground or from under stones. The end of the egg case that is attached 
to the stone is flat and sticky and the body of the case is a cylindrical 
tube, larger in the middle and smaller toward the free end where it is 
smooth and transparent. The free end is covered with a smooth, cup- 
like cap which is even more delicate than the rest of the case. This 
cap is forced off by the movement of the fully developed embryos, 
and the young free themselves through the hole. The individual egg 
cases contain 7 to 12 eggs or developing embryos, and since as many as 
45 eges in the same stage of development have been taken from a 
single mature female, it follows that each female deposits 5 or 6 
separate egg cases. The larvae are fairly typical salamander stream 
larvae. 
Cryptobranchidae.—The salamanders of this family, like those in 
the family Hynobiidae, practice external fertilization. In Crypto- 
branchus, the hellbender of the eastern United States, mating takes 
place in the late summer. ‘The male excavates a nest on the stream 
bottom beneath some large sheltering object, usually a flat rock, and 
will accept females that have not deposited their eggs. The eggs 
are laid in long rosarylike strings, one from each oviduct. These 
strings settle in a tangled mass on the bottom of the nest. As many 
as 450 eggs may be deposited by a single female, and several females 
may lay in a single nest. Fertilization is accomplished by the male 
discharging into the water a whitish, cloudy mass, consisting of semi- 
nal fluid and secretions of the cloacal glands, as the eggs are deposited 
by the female. After the eggs are deposited and fertilized, the male 
often lies among them with his head guarding the opening of the nest. 
It takes about 10 to 12 weeks for the eggs to hatch; the larvae trans- 
form at approximately 18 months. 
Ambystomatidae—tIn the family of the mole salamanders, two 
modifications not present in the previously mentioned families of 
salamanders show up: one is internal fertilization and the other is 
deposition of eggs on land. All the Ambystomatidae practice internal 
fertilization by means of spermatophores. These spermatophores are 
little packets of sperm, enclosed in a mushroom-shaped, gelatinous 
mass, which are deposited by the male and picked up by the cloacal 
lips of the female. Most of the ambystomatids, such as Ambystoma 
tigrinum, A. maculatum, and A. jeffersonianium, lay their eggs in 
water. In the last-named species, for example, the adults migrate to 
the breeding ponds in the early spring. The females usually outnum- 
ber the males and often must bid for attention during the mating 
season. After a characteristic courtship, the female picks up the 
spermatophore and deposits small eggs in cylindrical masses which 
