384 SMITHSONIAN MISCELLANEOUS COLLECTIONS [vor. 48 
found in any other nest; while in other nests that were twice as 
large as this one were found less than half as many eggs, showing 
that there is no relation between the size of the nest and the number 
of eggs. The average number of eggs per nest, in the twelve nests 
that were noted, was thirty-one. One observer reported a nest that 
contained sixty eggs, but this, if true, was a very unusual case. 
Reports of still larger numbers of eggs in one nest probably refer 
to crocodiles, which are said to lay one hundred or more eggs in 
a nest. Although crocodiles may be found in certain parts of 
Florida, the writer has had no opportunity of observing their nesting 
habits. 
The eggs are laid in the nest without any apparent arrangement. 
After the nest has been prepared, and has had time to settle prop- 
erly, the alligator scrapes off the top, and lays the eggs in a hole in 
the damp, decaying vegetation; the top of the nest is again rounded 
off, and it is impossible to tell, without examination, whether the 
nest contains eggs or not. 
As to whether the same nest is used for more than one season 
there is a difference of opinion among alligator hunters, and the 
writer has had no opportunity of making personal observations. 
While it is usually stated that the eggs are incubated by the heat 
of the sun, it is held by some observers that the necessary heat is 
derived not from the sun but from the decomposition of the vege- 
table matter of which the nest is composed. Possibly heat may be 
derived from both of these sources, but it seems likely that the 
conditions that are especially favorable to normal incubation are 
moisture and an even, though not necessarily an elevated tempera- 
ture. Moisture is certainly a necessary condition, as the porous 
shell allows such rapid evaporation that the egg is soon killed if 
allowed to dry. The inside of the nest is always damp, no matter 
how dry the outside may become under the scorching sun, so that 
this condition is fully met. The eggs of the Madagascar crocodile, 
according to Voeltzkow,’ offer a marked contrast to those of the 
alligator. Instead of being laid in damp’ nests of decaying vegeta- 
tion, they are laid in holes that are dug in the dry sand, and are 
very sensitive to moisture, the early stages, especially, being soon 
killed by the least dampness. 
The daily range of temperature in the southern swamps is some- 
times remarkably great, so that if the eggs were not protected in 
some way they would often pass through a range of temperature of 
* Voeltzkow, A., The Biology and Development of the Outer Form of the 
Madagascar Crocodile. Abhandl. Senckberg. Gesell., Bd. 26, Hft. I. 
