iI GLANDS OF TIIE SKIN 13 
sternum, is a naked patch of skin which is seen to be perforated 
by numerous pores. Besides the ordinary sebaceous and sweat 
glands there are a series of masses of glands, opening by larger 
orifices, which present the appearance of groups of sebaceous 
glands, and are of a racemose character ; but the existence of muscu- 
lar fibres in their coats seems to show that they should be referred 
rather to the sudoriparous series. Beneath the integument is a 
large compound tubular gland quite half an inch in diameter. 
In Didelphys dimidiata there is a precisely similar glandular 
area and large underlying gland, the correspondence being re- 
markable in two Marsupials so distant in geographical position 
and affinities. Even among the Diprotodont genera there is 
something of the kind; for in Dorcopsis luctuosa and D. muelleri 
is a collection of four unusually large sebaceous follicles upon 
the throat, and in the Tree Kangaroo (Dendrolagus bennettii) 
there is the same collection of enlarged hair-follicles, though 
they are apparently somewhat reduced as compared with those of 
Dorcopsis. These are of course a few examples out of many. 
-It seems to be possible that the functions of these various 
glands is at least twofold. In the first place, they may serve, 
where predominant in one sex, to attract the sexes together. 
In the second place, the glands may be useful to enable a strayed 
animal of a gregarious species to regain the herd. It is perfectly 
conceivable too that in other cases the glands may be a protec- 
tion, as they most undoubtedly are in the Skunk, from attacks. 
In connexion with the first, and more especially the second, of 
the possible uses of these glands, it is interesting to note that 
in purely terrestrial creatures, such as the Rhinoceros, the glands 
are situated on the feet, and would therefore taint the grass and 
herbage as the animal passed, and thus leave a track for the 
benefit of its mate. The same may be said of the rudimentary 
glands of Horses if they are really glands. The secretion of the 
“crumen” of Antelopes is sometimes deposited deliberately by 
Oreotragus upon surrounding objects, a proceeding which would 
attain the same end. One may even perhaps detect “mimicry ” 
in the similar odours of certain animals. Prey may be lured to 
their destruction, or enemies frightened away. The defenceless 
Musk-deer may escape its foes by the suggestion of the musky 
odour of a crocodile. It is at any rate perfectly conceivable 
that the variety of odours among mammals may play a very 
