804 MAMMALIA. 



No covering of hair or wool would have been efficient in retaining the 

 vital heat under the circumstances in which these creatures live ; and 

 even if such clothing could have been made available, it would have 

 seriously impeded their progress through the water. Another kind of 

 blanket has therefore been adopted : the cuticle is left perfectly smooth 

 and polished, without any vestige of hair upon its surface ; but, be- 

 neath the skin, fat has been accumulated in prodigious quantities ; and, 

 enveloped in this non-conducting material, the Whales are fully pre- 

 pared to inhabit an aquatic medium, and to maintain their temperature 

 even in the Polar Seas. 



(2352.) The skin of all quadrupeds contains innumerable secerning 

 follicles, whereby lubricating fluids are continually furnished for the 

 purpose of maintaining the surface in a moist or supple condition ; but 

 not unfrequently these glandular follicles are aggregated together in 

 considerable numbers, so as to form secreting pouches. In many species 

 of Stags and Antelopes, for example, large pouches of this description 

 are found below the margin of the orbit, that furnish a secretion vul- 

 garly regarded as the Stag's " tears." In most instances some of the 

 cutaneous glands secrete a highly odorous material, especially in the 

 vicinity of the parts of generation; and their secretion being most 

 abundant during the rutting season, it is not without reason that these 

 organs are looked upon as destined to attract the sexes, and perhaps to 

 stimulate the sexual passions. The preputial glands, so called because 

 they furnish an odoriferous fluid that lubricates the prepuce and glans 

 of the penis in the male, and of the clitoris in the female, are of this 

 kind *. For the most part, these are simple sebaceous follicles con- 

 tained in the thickness of the prepuce ; but occasionally they are re- 

 placed by true conglomerate glands, formed of lobes and lobules, and 

 having but a single excretory duct, that opens upon the sides of the 

 glans penis or ditoridis beneath the prepuce. Many of the Rodentia 

 are furnished with glands of this description, and they are situated on 

 each side of the penis, immediately beneath the skin that covers the 

 pubic region. 



(2353.) It is with the preputial glands that we must notice the still 

 more elaborately- developed secreting organs of the Beaver, that furnish 

 the drug called " castor." These organs, represented in the annexed 

 figure (fig. 405), consist of large glandular pouches (g, A), that discharge 

 their contents in the vicinity of the anal and preputial apertures ; but 

 of what importance the material thus abundantly secreted may be in 

 the economy of the animals so provided, it is not easy to conjecture. 



(2354.) The secreting apparatus of the Musk Deer (Moschus moschi- 



ferus), which produces musk, is of analogous conformation. This is an 



oval pouch situated beneath the skin of the lower part of the belly : its 



walls are thin, and apparently membranous; but the membrane that lines 



* Cuvier, Legons d'Anat. Comp. v. p. 252 et seq. 



