48 
HORN EXPEDITIOX—MAMMALIA. 
Left Lower Jaw. 
One specimen with 7 teeth ... 
... 7 
Five specimens with 8 teeth each 
... 40 
Nine specimens with 9 teeth each 
... 81 
Nine specimens with 10 teeth each 
... 90 
One specimen with 11 teeth 
... 11 
Total 
... 229 
Right Lower Jaw. 
One specimen with 5 teeth ... 
5 
Six specimens with 8 teeth ... 
... 48 
Eight specimens with 9 teeth 
... 72 
Nine specimens with 10 teeth 
... 90 
One specimen with 11 teeth 
... 11 
Total 
... 22G 
If we take into account the fact that one specimen included in the above is 
very old, and that on one side of the lower jaw all the teeth have dropped out in 
front of the large premolar, whilst two remain on the other side, it will be seen 
that there is scarcely any discrepancy between the numbers of teeth developed so 
far as the total is concerned. There is, however, a very considerable amount of 
variation present in different individuals, both with regard to the number and also 
the form of the teeth in front of the large premolar. 
The pouch .—This varies very much according to the time of year at which 
the animal is caught; and judging from the examination of a considerable number 
of female specimens caught at various times, I think that the breeding season will 
be found to be in or about November, 
The largest pouch present (in a specimen captured in January) measured 
from its very posterior to its anterior end 17'5 mm., though the portion enclosed 
by the ventral wall measured 9 mm. The opening is thus an elongate, backwardly- 
sloping one. The greatest width of the pouch was 12 mm. and the depth 8 mm. 
It is divided into two halves by a ridge on the abdominal wall, in such a way that 
at the anterior end two lateral bays are completely separated off from each other 
for a short distance. Two mammary elevations, placed one at the commencement 
of each lateral bay, are present of considerable size, and (after the animal had 
