UEPKODUCTIVE CYCLE IN DASYURUS ViVEKlMNUS. 139 
Dasyurus lias only one breeding season^ in the year, which 
extends over the winter months, i. e. from the end of May to 
the first fortnight in August. 
In our records there are two cases of females ovulating in 
May; one killed on the 21st had eggs which had just entered 
the uteri, and the other, killed on the 31st, showed corpora 
lutea in a very early stage. The two latest records of preg- 
nant females are on the 2nd and 6th of August, and in both 
cases the embryos were in an advanced condition. 
The male does not appear to experience an obvious period 
of rnt, such as Semon (25) describes for the male Phasco- 
larctos. We have, however, frequently observed that the 
substitution of another male for the one previously with a 
female frequently resulted in copulation (cf. record, p. 151). 
The records show that copulation may extend intermittently 
ever a period of two to three days. In the majority of cases, 
however, there is only a single record of coition, generally 
lasting for several hours. 
The method of copulation in Dasyurus is similar to that 
described by Selenka for Didelphys (23, p. 105), the male 
mounting on the back of the female and laying hold of the 
skin of the dorsum of the neck with his jaws. The penis, 
when erected, is extremely long and attenuated and possesses 
a markedly bifid glans, its two divisions doubtless being- 
inserted into the corresponding lateral vaginal canals. The 
records show that the spermatozoa may remain alive in the 
Fallopian tubes (where they occur in large bunches in the 
gland lumina opening into same) for at least two weeks. 
Pro-cestrus. 
So far as our observations extend, there is no evidence of 
any animal ovulating twice in the same season, nor is there 
1 This term is used in the sense defined by Heape (11), i.e. 'To denote 
the whole of that consecutive period during which any male or female 
mammal is concerned in the production of young,” and does not include 
the period of suckling. 
