HORN EXPEDITION—MAMMALIA. 
49 
been pre.served in alcohol) they are hard, smooth and white, with a very distinct 
little brown nipple at the apex of each. They are in appearance very unlike the 
mamime of other marsupials; so much so, that until we examined them closely, 
Mr. Byrne and myself both thought that they were the smooth naked bodies of 
small pouch embryos attached to the teat, and that the little brown nipple was the 
minute tail. 
The most curious point, however, in regard to the pouch is that, in examining 
thirty specimens, eight of them showed what I took at first to be the commence¬ 
ment of the development of the pouch, which varies considerably in size in the 
female. Though the indentation of the skin was slight, it was at once recognisable 
when the thick hairs covering the abdomen wei’e pushed to the sides so as to 
leave the middle line relatively bare. It lies about 8 mm. in front of the anus— 
just the right position for a minute pouch—and has, moreover, a few very dark 
brown hairs arising from the indentation, exactly such as are present in the well- 
developed pouch of the female. 
Dissection of two of the animals proved at once that they were males, so that 
in Notoryctes t]ie7'e may be developed the nidiment of a pouch in the male. 
Marsupial bones. —In the original description of Notoryctes, drawn up from 
specimens which were not in a good state of preservation, these were described as 
small nodules in the tendon of the external oblique muscles of the abdomen. In 
three of my specimens in a good state of preservation, which have been examined, 
the marsupial bones are well developed, each is 4-5 mm. in length, and they 
diverge as usual from the anterior border of the pubic symphysis. 
Reproductive organs. —From the examination of female specimens, in which the 
pouch is well developed and shows two mamime (as already described by Dr. 
Stirling), we have been able to determine the structure of the reproductive 
organs. The only satisfactory way of doing this is by means of serial sections, 
which show that they are formed in a typical marsupial mannei’, with two 
lateral vaginie. The median canal is closed, and the structure of the organs is 
closely similar to that of Hypsiprymodon. 
So far as the reproductive organs are concerned, they show, as every other 
organ of the body does, that Notoryctes is merely a marsupial modified so as to 
adopt the burrowing habit. It is in no manner whatever an intermediate form 
between Monotremes and Marsupials. 
Notoryctes, though essentially a burrowing animal like the European mole, 
differs from the latter in not forming a permanent burrow ; that is, it has no 
a 
