276
L. G A L L I E N
ments represent the reversal of the male phenotype to the female phenotype by suppression of the androgenic hormone.
The major conclusions from these studies are the following. When a
genetic male or female amphipod, of the 0. gammarella type, undergoes
sexual differentiation in the absence of the androgenic gland, whether this
gland does not differentiate (genetic females) or whether it is suppressed
surgically (genetic males), the individual develops as a female: ovaries,
oostegites, undifferentiated gnathopods. The sexually neutral type of
gonad, that is, the one that differentiates in the absence of hormones, is the
female type. The presence of the androgenic hormone is necessary in both
sexes to induce testicular differentiation and the male type of gnathopods
and to inhibit the differentiation of oostegites.
The testis itself does not have an endocrine function. The androgenic
gland, attached to the sperm duct, represents in the male the androgenic
endocrine tissue. This is spatially separate from the germinal tissue. On the
other hand, the ovary, in the course of its development, becomes an endocrine structure; it secretes one or more ovarian hormones that control the
development of the oostegites and the presence of bristles. Only the androgenic gland has the capacity to reverse a female to a male.
It is appropriate to note here that the crustaceans have continuous
growth, in contrast to the insects, and that the differentiation of the sex
of the gonad is not definitively established at a given time in development,
as it is in the vertebrates.
In 0. gammarella, offspring of two genetic females reversed to physiologic
males (neomales) have been obtained by artificial fertilization, after crossing with normal genetic females. These crosses produced, respectively,
9 9 :3 d
71
and 24 9 :31 d \ a total of 33 9 and 34 cf. This result, which
must be extended to include more offspring for statistical reliability, tends
to show that the female is heterogametic in this amphipod (ZW 9 :ZZ d
1 ).
2. Isopods
In the Oniscoidea, Porcellio dilatatus and Helleria brevicornis, the transformation of genetic females to functional males (neomales) has been
obtained by grafting androgenic glands (Juchault and Legrand, 1964a,b),
and also in Armadillium vulgäre (Katakura, 1961). Such neomales crossed
with normal genetic females have produced, in the three species, exclusively
female offspring (Katakura, 1961; Juchault and Legrand, 1964c). This
result indicates that the female is the homogametic sex in these isopods
( X X 9 : X Y c ^ ) .
8. Decapods
The shrimp, Lysmata seticauda, is normally a protandric hermaphrodite.
In grafting androgenic glands to an individual in the female phase,
Charniaux-Cotton (1959b, 1961b) has masculinized them.
L. G A L L I E N
ments represent the reversal of the male phenotype to the female phenotype by suppression of the androgenic hormone.
The major conclusions from these studies are the following. When a
genetic male or female amphipod, of the 0. gammarella type, undergoes
sexual differentiation in the absence of the androgenic gland, whether this
gland does not differentiate (genetic females) or whether it is suppressed
surgically (genetic males), the individual develops as a female: ovaries,
oostegites, undifferentiated gnathopods. The sexually neutral type of
gonad, that is, the one that differentiates in the absence of hormones, is the
female type. The presence of the androgenic hormone is necessary in both
sexes to induce testicular differentiation and the male type of gnathopods
and to inhibit the differentiation of oostegites.
The testis itself does not have an endocrine function. The androgenic
gland, attached to the sperm duct, represents in the male the androgenic
endocrine tissue. This is spatially separate from the germinal tissue. On the
other hand, the ovary, in the course of its development, becomes an endocrine structure; it secretes one or more ovarian hormones that control the
development of the oostegites and the presence of bristles. Only the androgenic gland has the capacity to reverse a female to a male.
It is appropriate to note here that the crustaceans have continuous
growth, in contrast to the insects, and that the differentiation of the sex
of the gonad is not definitively established at a given time in development,
as it is in the vertebrates.
In 0. gammarella, offspring of two genetic females reversed to physiologic
males (neomales) have been obtained by artificial fertilization, after crossing with normal genetic females. These crosses produced, respectively,
9 9 :3 d
71
and 24 9 :31 d \ a total of 33 9 and 34 cf. This result, which
must be extended to include more offspring for statistical reliability, tends
to show that the female is heterogametic in this amphipod (ZW 9 :ZZ d
1 ).
2. Isopods
In the Oniscoidea, Porcellio dilatatus and Helleria brevicornis, the transformation of genetic females to functional males (neomales) has been
obtained by grafting androgenic glands (Juchault and Legrand, 1964a,b),
and also in Armadillium vulgäre (Katakura, 1961). Such neomales crossed
with normal genetic females have produced, in the three species, exclusively
female offspring (Katakura, 1961; Juchault and Legrand, 1964c). This
result indicates that the female is the homogametic sex in these isopods
( X X 9 : X Y c ^ ) .
8. Decapods
The shrimp, Lysmata seticauda, is normally a protandric hermaphrodite.
In grafting androgenic glands to an individual in the female phase,
Charniaux-Cotton (1959b, 1961b) has masculinized them.