232 The Alligator and Its Allies 
before he succeeded in obtaining all the desired 
stages of development. 
To obtain the earliest stages, I watched the 
newly made nests until the eggs were laid, and in 
this way a number of eggs were obtained within a 
very few hours after they had been deposited, and 
all of these eggs contained embryos of a more or 
less advanced stage of development. Gravid 
females were then killed, and the eggs removed 
from the oviducts. These eggs, although removed 
from a ‘‘cold-blooded”’ animal, generally contained 
embryos of some size, and only one lot of eggs thus 
obtained contained undeveloped embryos, which 
embryos refused to develop further in spite of the 
most careful treatment. Voeltzkow (78) found, 
in the same way, that the earlier stages of the 
crocodile were extremely difficult to handle; so 
that, in order to obtain the earlier stages, he was 
reduced to the rather cruel expedient of tying 
a gravid female and periodically removing the eggs 
from the oviducts through a slit cut in the body 
wall. 
The older embryos are hardy and bear trans- 
portation well, so that it is comparatively easy 
to obtain the later stages of development. 
For the stages up to the formation of the first 
four or five somites, I am indebted, as I have 
already said, to Professor Clarke, and, since I 
have had opportunity to examine only the sections 
and not the surface views of these stages, I shall 
