1875.] PROF. W. H. FLOWER ON THE MUSK-DEER. 187 
also be noticed, and perhaps accounted for in the same manner ; but 
until the livers of all other species of Deer have been examined, its 
significance cannot be properly estimated. 
VI. In the same category may be placed the presence of Cowper’s 
glands, organs generally absent in the Deer and present in all the 
other Artiodactyla. But although the examination into this question 
has not yet been very searching, exceptions have already been found. 
Their presence in the Pudu has been noted above ; and their absence 
in the Prongbuck (Antilocapra), an animal which though aberrant 
I cannot but place among the Bovine section of the group, has been 
recorded by Dr. Murie in his valuable description of the anatomy of 
that animal*. 
Together with the absence of Cowper’s glands, the Deer have a 
form of penis unknown in other Artiodactyles, and to which Moschus 
does not quite conform ; but closer investigations are required before 
the value of this character can be ascertained. 
VII. The cutaneous glands. Some importance as a taxonomic cha- 
racter has been attached by zoologists to the abdominal odoriferous 
gland for which the Musk-Deer is so well known. This has been 
given, for instance, as one of the family characters by which Moschus 
has been separated from the Deer on the one hand and the Chevro- 
tains on the other. But its importance has been overrated, from the 
supposition that it was a structure sui generis instead of only one of 
the numerous modifications of specialized patches of involuted inte- 
gument found so universally throughout the vertebrate animals, pro- 
bably always for a similar purpose at present not perfectly understood, 
but evidently connected with the discovery and recognition of the 
presence of individuals of the same species in the neighbourhood. 
Such glandular patches, either of the skin extended in its usual 
manner over the surface, or more or less involuted so as to produce a 
pouch in which the secretion may be retained for a time and its 
effect thus intensified, are abundantly developed and most variously 
located in the Artiodactyla—as below thelower jaw in the Chevrotains, 
on the forehead in the Muntjaks, behind the ear in the Chamois, 
_ below the ear in the Prongbuck, in front of the eye (the crumen) in 
a vast number of species, on the middle of the back in the Peccaries, 
beneath the tail in Goats, within the edge of the prepuce in the Pigs, 
some Antelopes, and Moschus, in the inguinal region in many 
Antelopes, on the outside of the metatarsus in most Deer, between 
the toes in so many species ; and their presence or absence, though 
extremely interesting to observe in each species, especially with a 
hope to discover more of their function, is not so constantly corre- 
lated with other characters as to enable us to make use of them in 
classification. otherwise than in distinguishing very minor groups. 
There are, in fact, few parts of the organization so variable and 
readily modified. 
* P.Z.8. 1870, p. 334. 
+t Although the first commencement of the modifications of portions of 
the external covering for the formation of special secretions may be at, 
present difficult to understand, the principal of natural selection will readily 
