REPEODUCTIVE CYCLE IN DASYURUS VIVERRINUS. 165 
Met oestrus. — This is an indefinite period during which 
the whole of the reproductive organs return to a state of rest. 
Conclusions. 
Comparison of the QEstral Cycles in the Metatheria 
and Eutheria. 
A comparison of the tables of the cestral cycle in the non- 
pregnant Dasyurus and in the non-pregnant Eutherian (pp. 
163-164)^ following the schemes of Heape (11) and Marshall 
(18), discloses certain rather striking and important differences 
between them. These differences are seen at a glance in the 
Scheme of Reproductive Cycle in- 
(1) Dasyurus. 
Anoestms. 
(2) Eutherian. 
Anoestrus. 
Pro-oestrus. 
(Estrus. 
Pro-oestrus (uterine degeneration). 
I 
(Estrus 
(ovulation). 
Post-oestrus (ovulation). 
L 
I I 
Pregnancy. Pseudo-pregnancy Pregnancy, 
(uterine degeneration). I 
Nursing period. Metoestrus. Nursing period. 
I I J 
I 
Dioestrus. ^ 
I I 
Metoestrus. 
Anoestrus. Anoestrus. 
1 This period only occurs in polyoestrous animals. 
scheme which we have drawn up of the reproductive cycle 
in the Marsupial (as represented by Dasyurus), and what may 
be taken to be the usual cycle in the Eutherian mammal as 
set forth by Heape and Marshall. They concern more espe- 
cially the time-relations of the degenerative uterine changes 
