MAMMALIA. 691 



veloped secreting organs of the Beaver, that furnish the drug 

 called " castor" These organs, represented in the annexed figure 

 (Jig. 319), consist of large glandular pouches, g, A, that discharge 

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

 but of what the importance of the material thus abundantly se- 

 creted may be in the economy of the animals so provided, it is not 

 easy to conjecture. 



(794.) The secreting apparatus of the Musk Deer, (Moschus 

 moschiferus,) which produces musk, is of analogous conforma- 

 tion. 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 them is rugose and 

 plicated. The orifice leading to this pouch is small, and opens 

 in front of the prepuce. 



(795.) Lastly, in connection with these odoriferous glands 

 we may mention the " temporal glands" of the Elephant, from 

 the duct of which, situated on each side midway between 

 the eye and the ear, there flows a viscid and fetid liquid ; 

 and likewise the u anal glands" met with in most CARNIVORA. 

 The ducts of the glands last mentioned open near the margin of the 

 anus ; and in some genera, as the Skunk and the Polecat, the 

 stench produced by the fluid poured from these sources is so into- 

 lerable as to become a most efficient defence against a foreign enemy. 



(796.) We now come to consider the nervous system of the 

 MAMMALIA, and are of course prepared to anticipate that in pro- 

 portion as they surpass all other animals in intelligence, so will the 

 encephalic masses assume a complexity and perfection of structure 

 such as we have not hitherto witnessed in the whole series of 

 the animal creation . Their senses likewise may be presumed to 

 have attained the utmost delicacy of organization in correspond- 

 ence with the exalted attributes conferred upon this important 

 class, and consequently to exhibit appendages and accessory parts, 

 adapting them most accurately to repeat to the sensorium impres- 

 sions derived from without. 



(797.) Abstruse as the study of the brain has been rendered by 

 the chaotic assemblage of names applied by the earlier anatomists 

 in their bewilderment to every definable portion of its substance, 

 we have little doubt that, when the grand laws that have hitherto 

 guided us in investigating the nervous system of the lower animals 

 are had recourse to, the student will soon perceive how little diffi- 

 culty there is in comparing even the brain of Man with the ence- 



2 Y 2 



