KEPKODUOTIVE OVOLE IN DASYURUS VIVERRINES. 153 
(2) A free period, during wliicli tlie lips of the young 
animal are no longer fused, so that it can leave the teat at 
will, but is still entirely dependent on its mother for food. In 
Dasyurns, this period extends over eight or nine weeks. The 
total time occupied by these two periods, which together 
form the true nursing period, is about four months in Dasy- 
urus ( 13 ). 
After this period, the young move about freely away from 
the mother, and begin to eat, although they still may make 
occasional use of the pouch. 
This marks the conclusion of the reproductive cycle, and 
the various oi’gans now return to an anoestrous condition, or 
state of rest, until the following year. 
Pseudo-Pregnancy. 
Ovulation is followed by the formation of corpora lutea. 
According to Ancel and Bonin ( 1 ), in animals in which ovu- 
lation is spontaneous, two distinct kinds of corpora lutea are 
formed; {a) in the pregnant animal, a gestative corpus 
luteum (corpus luteum verum), which persists for a long time, 
and (h), in the non-pregnant animal, a periodic corpus 
luteum (corpus luteum spurium), which is not so fully 
developed as the former, and has only a transitory existence- 
No such distinction is possible in Dasyurus, for the structure 
of the corpus luteum is identical, whether pregnancy follows 
ovulation or not, and there is evidence to show that in the 
non-pregnant animal the corpus luteum persists for a consid- 
erable time, some weeks at least, and even then shows no sign 
of degeneration (vide 21). 
The pouch continues to enlarge after ovulation, and the 
sweat and sebaceous glands of the pouch area reach a state 
of development and activity comparable to that attained in 
the pregnant animal. In some cases, it was observed that the 
female started to clean out the pouch in the same wa}^ as does 
the pregnant female, in preparation for the reception of the 
young. 
