Vie CONG. INTERN. REPROD. ANIM. INSEM. ARTIF., PARIS, 1968, VOL. 1l

the first was a female pseudohermaphrodite with XX sex chromo-
somes, the second was a male pseudohermaphrodite with XY chromo-
somes, and the third was a true hermaphrodite with XX chromosomes

only.
Mink

A single case of a true hermaphrodite has been described
in the mink. This case was a mosaic with a 30XX/45XXY chromo-

some constitution (Nes, 1966) .

SPECIAL PROBLEMS

Three special problems are considered in this review:
(1) The incidence of chromosomal aberrations in utero,
(2) The origin of the XX/XY sex chromosome constitution, and
(3) The role of the Y chromosome in testicular development.
The problem of freemartinism will not be considered other than
the fact it involves XX/XY chimerism. Further discussion of
freemartinism, particularly as to whether it has a humeral or
cellular origin, is given by Biggers and McFeely (1966),
ohno (1967), Gerneke (1967), Herschler and Fechheimer (1967),
Short (1968) and Dunn, Lein and Kenney (1968) .

Incidence of chromosomal aberrations
in utero
There is considerable evidence that embryonic death is

considerable even in animals considered to be normally fertile

851 UNIVERSITY OF
JILLINOIS LIBRARY,