of the spinal cord, however, indicated the individual was a
genetic female. This case provides the best evidence in the pig

that a genetic female may be invaded by male cells.

Cat

The sex chromosomes have now been studied in eight cases
of tortoiseshell cats. The results are summarized in Table 4.
The condition arises with an XXY sex chromosome constitution
alone and in various chimeric combinations. The reason these
cases have received so much attention is because of the associa-
tion of the hair colours with the sex chromosomes, the tortoise-
shell coat pattern acting as a marker for the intersexual con-
ditions (see Biggers and McFeely, 1966, for a review). The
case recently described by Malouf, Benirschke and Hoefnagal
(1967) is of considerable interest since the animal had a
functional testes undergoing spermatogenesis and the tortoise-
shell coat colour. This chimeric combination may account for
the very rare cases of fertile male tortoiseshell cats which

have been described.

Dog
The chromosome constitutions of only three cases have
been studied in the dog (McFeely and Biggers, 1965: McFeely,

Hare and Biggers, 1967) (Table 4). All three are different;

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