160 
J. P. HILL AND CHAS. H. o’dONOGHUE. 
is reconstituted^ and the low cubical epithelium of the uterine 
glands persists like that of the post-partum uterus to form 
the lining of the resting glands. The connective tissue re- 
assnmes its more compact form, and the mucosa as a whole 
undergoes marked decrease in thickness and returns to the 
condition of rest. 
It is difficult, indeed, impossible, to ascertain the exact 
duration of this period of pseudo-pregnancy, but so far as we 
can judge with the aid of our records, it probably extends over 
about two weeks. We have, for example, a very full record of 
a female, apparently in heat about June 28th and killed on 
July 15th, i. e. seventeen days after heat, and of another 
female in heat on June 9th (copulation on June 9th to 12th) 
and killed on June 30th, i. e. twenty-one days after heat. In 
both, nothing was found in the uteri. In both, the ovaries 
showed old corpora lutea, the pouch was greatly enlarged the 
mammary and other glands being well-developed, whilst the 
uteri were extremely large and vascular (measuring in the 
first-mentioned female by 4 by 1 cm. and in the second 3*9 
by 4'1 by T6 cm. in diameter). 
Metcestrus. 
After the changes described in the preceding section have 
taken place, the whole of the reproductive organs gradually 
return to a state of rest. This metoestral period corresponds 
functionally to the similarly named one in the Eutheria, only 
there is the striking difference that, whereas in the unimpreg- 
nated Eutherian mammal, metoestrum follows immediately 
after ovulation, in the unimpregated marsupial, the two are 
separated by post-oestrus and psendo-pregnaucy, the two 
periods together occupying at least a fortnight, and probably 
longer. 
Summary. 
Dasyurus is mouoestrous and has one breeding season a 
year, wdiicli begins at the end of May or early in June and 
