GLANDS OF THE 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 Didelpliys 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 gregaxious 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 Ehinoceros, 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 



