214
WILLIAM C. YOUNG
in adults. Pesonen and Rapola (171), on the other hand, could find no
steroid dehydrogenase activity in the ovaries of Xenopus hevis and Bufo
bufo and concluded that there is no appreciable production of steroids
in the ovaries of these species. They suggest that such hormones originate
in adrenal tissue in which there was invariably a distinct dehydrogenase
activity. The inconsistency of their hypothesis with the isolation of estrogens by Gallien and Chalumeau-Le Foulgoc was recognized.
Another difficulty centers around the hormonal activity of the corpus
luteum. Whether this structure is preovulatory (142) or postovulatory
(170, 173), it forms from the follicular epithelium (granulosa cells) and
is surrounded by a thin but compact capsule of thecal tissue. Bretschneider and Duyvene de Wit (142) believe that the granulosa cells produce
a sex hormone which acts on the accessory reproductive organs. At this
time the possibility that this substance is progesterone should not be
rejected; indirect evidence has been obtained that progesterone or a
close derivative is present about the time of ovulation in the ovaries
of Bufo arenarum (174) and Rana pipiens
(175).
When we look at the Amphibia it is only too obvious that many gaps
must be filled before we will have a reasonably satisfying understanding
of the relationship between the hormones and behavior. It seems clear,
however, unless confirmation is given to the hypothesis that the adrenal
cortex rather than the ovary is the main source of estrogens in the female
(171), that no tissue relationship or hormone not represented in the
other vertebrates is involved in the induction of reproductive behavior.
The broad significance of the relationship of the hypophyseal hormone
prolactin to the migration of efts to and from land and water (43-46)
appears not to be known. The relationship could be a specialization
peculiar to certain amphibians or it could be a variation of other relationships between the hypophysis and behavior which have appeared
in other phyla.
VI. Reptiles
Dodd (123) reminds us in his discussion of the hormones and reproduction in reptiles that internal fertilization which has become universal
in this group has involved the development of copulatory organs and
specialized mating behavior. Despite these important developments, less
is known about the relationship between the hormones and behavior in
reptiles than in members of the other vertebrate phyla. Quantification
can hardly be claimed to have been attempted, but from the descriptive
studies of turtles and lizards (176-187) and from the many short reports
in the herpetological journals, the patterns of aggressive, territorial,
courtship, mating, oviposition, and brooding behavior (in the sense of
WILLIAM C. YOUNG
in adults. Pesonen and Rapola (171), on the other hand, could find no
steroid dehydrogenase activity in the ovaries of Xenopus hevis and Bufo
bufo and concluded that there is no appreciable production of steroids
in the ovaries of these species. They suggest that such hormones originate
in adrenal tissue in which there was invariably a distinct dehydrogenase
activity. The inconsistency of their hypothesis with the isolation of estrogens by Gallien and Chalumeau-Le Foulgoc was recognized.
Another difficulty centers around the hormonal activity of the corpus
luteum. Whether this structure is preovulatory (142) or postovulatory
(170, 173), it forms from the follicular epithelium (granulosa cells) and
is surrounded by a thin but compact capsule of thecal tissue. Bretschneider and Duyvene de Wit (142) believe that the granulosa cells produce
a sex hormone which acts on the accessory reproductive organs. At this
time the possibility that this substance is progesterone should not be
rejected; indirect evidence has been obtained that progesterone or a
close derivative is present about the time of ovulation in the ovaries
of Bufo arenarum (174) and Rana pipiens
(175).
When we look at the Amphibia it is only too obvious that many gaps
must be filled before we will have a reasonably satisfying understanding
of the relationship between the hormones and behavior. It seems clear,
however, unless confirmation is given to the hypothesis that the adrenal
cortex rather than the ovary is the main source of estrogens in the female
(171), that no tissue relationship or hormone not represented in the
other vertebrates is involved in the induction of reproductive behavior.
The broad significance of the relationship of the hypophyseal hormone
prolactin to the migration of efts to and from land and water (43-46)
appears not to be known. The relationship could be a specialization
peculiar to certain amphibians or it could be a variation of other relationships between the hypophysis and behavior which have appeared
in other phyla.
VI. Reptiles
Dodd (123) reminds us in his discussion of the hormones and reproduction in reptiles that internal fertilization which has become universal
in this group has involved the development of copulatory organs and
specialized mating behavior. Despite these important developments, less
is known about the relationship between the hormones and behavior in
reptiles than in members of the other vertebrate phyla. Quantification
can hardly be claimed to have been attempted, but from the descriptive
studies of turtles and lizards (176-187) and from the many short reports
in the herpetological journals, the patterns of aggressive, territorial,
courtship, mating, oviposition, and brooding behavior (in the sense of