150 
J. P. HILL AND CHAS. H. o’dONOGHUE. 
that the circumstances in this particular case were not normal, 
since this female was no doubt in a cowed and frightened 
condition when placed in the cage with the male. 
We have another record of a female^ in which the young 
were born sixteen days after copulation. This particular 
female was received on June 20th. Copulation occurred 
on the 24th, and parturition on July 10th. This record 
we regard as perfectly trustworthy. The question as to when 
ovulation occurred, however, cannot be answered with any 
degree of accuracy. We have already stated that ovulation 
occurs at a variable period after oestrus. In our records we 
find that the shortest time intervening between copulation 
and the finding of unsegmented eggs in the uteri is four 
days (in this particular case the eggs were in the uusegmented 
and 2-celled stages), and the longest time, eight days. 
Between these limits we have records of the following : five 
days after, no ovulation (three cases) ; five days after, un- 
segmented ova (one case) ; five days after, unsegmented and 
2-celled eggs (one case) ; five days after, 4-celled eggs 
(one case) ; six days after, unsegmented ova (one case) ; six 
days after, 2-celled eggs (one case) ; seven days after, 
unsegmented ova (one case). 
The average interval between copulation and ovulation 
would thus appear to vary round about five or six days. If, 
now, we subtract five from the sixteen-day record given 
above, we have a gestation period of about eleven days. 
From the evidence we think we are justified in stating that 
the gestation period in Dasyurus is not less than eight, and 
does not exceed fourteen days. 
General Changes. 
The ovarian changes following ovulation, i. e. those result- 
ing in the formation of the corpora lutea, have been fully 
1 This female is the one previously referred to (ante, p. 148) as having 
given birth to eighteen young. 
