REPRODUCTIVE CYCLE IN DASYURUS VIVERRINUS. 147 
Ovulation. 
It has been pointed out by Ancel and Bouin (1) that tlie 
Eutherian manimals may be divided into two classes according 
to the conditions under which they ovulate. In the first 
group ovulation is spontaneous — i. e. it takes place whether 
there has been coition or not (this condition appears to be 
the more general) ; whilst in the second group ovulation is 
non-spontaneous — i. e. in the normal course of events, copu- 
lation is necessary to provoke it. 
In Easy urns, ovulation is spontaneous and quite independent 
of copulation. We have records of nine females which 
ovulated after being under observation for periods varying 
from two to thirty-seven days, during which no copulation 
was seen to take place. Four of these females were under 
observation for twenty days and upwards, whilst in three of 
them, the unfertilised ova were found in the uteri. On the 
other hand, as pointed out above, we have records of five 
animals in which copulation had taken place but ovulation 
had not, three of these females having been killed five days 
after copulation. This evidence shows conclusively that 
ovulation and copulation are perfectly independent one of 
the other, and that the former is in no way provoked by the 
latter, as is the case, for example, in the rabbit. 
A further point in connection with ovulation is worthy of 
attention, although it has already been noted elsewhere 
(Hill (14) ), and that is the remarkable number of eggs dis- 
charged from the ovary at each ovulation. In one case 
twenty-eight eggs, in two others thirty eggs, and in yet 
another thirty-five vesicles were obtained from the two uteri. 
There can be no doubt that Dasyurus, like various other 
marsupials — e. g. Perameles, Macropus, etc. — has suffered a 
progressive reduction in the number of young reared, but, even 
making due allowance for that, the excess in production over 
requirements would still be remarkable enough ^ (Hill (14) ). 
^ Examination of the ovaries of D. maculatus with full-grown 
follicles shows that the same excessive production of ova holds true also 
for this species. 
