30 Trans. Acad. Sci. of St. Louis 
dominate in numbers, but later the females come out 
of hibernation rapidly and tend to equalize the ratio. 
Matings take place freely in this early period and since 
the males are out of hibernation first, and in such num- 
bers, the insemination of the females is insured. . . In 
May before ovulation there are usually about 32 eggs 
in the ovaries. . . It is evident that maturation occurs 
immediately preceding ovulation, and that fertilization 
occurs immediately after the entrance of the eggs into 
the ostium. The same female may copulate more than 
once, but ovulation of all the eggs takes place at nearly 
the same time. . . Eggs are laid under a ledge of rock 
in dirt and nicely concealed and covered from May until 
July. The incubation period is not known.’’ Reese 
(1922) found that a female had laid three yellowish eggs 
on the night of June 7. Later, dissection showed 34 
eggs inside of the body, similar to those laid before. 
Taylor (unpublished) stated that ‘‘The period of in- 
cubation is from four to five weeks.’’ Cahn (1926) has 
called attention to the fact that a number of prominent 
zoologists have overlooked the knowledge of the egg- 
laying habits of certain species of the genus Phryno- 
soma. He has also given another interesting account 
of the nest digging habits of P. cornutum, stating that 
‘‘Qn the afternoon of May 30, 1921, I chanced upon a 
female standing motionless on her toes in the center 
of a grassless, sunbaked area. The time wals about 
6:15 p.m. After about five minutes she began to dig. 
The work was leisurely done, but progressed steadily. 
... The lizard paid not the slightest attention to me, 
so early in the game I moved over and sat with her 
between my legs, the better to watch her operations. She 
permitted me to measure the hole, submitting to handl- 
ing without objection, and resumed her digging opera- 
