1-84 



MAMMALIA. 



which prey most extensively and exclusively on 

 \varm blooded animals. 



CHEIROPTERA. This family consists of two genera, 

 the great genus of the bats, and the Galeopithecus, 

 which is not a flying animal as the bats are, though 

 it resembles them in some parts both of its organisa- 

 tion and its habits, and is furnished with a leaping 

 membrane or parachute of ample dimensions. The 

 details of the structure arid action of the bats have 

 been already given in the section upon the flying 

 organs of the mammalia ; and some notice of the 

 species, and some popular accounts of the habits, will 

 be found in the article BAT, and the article GALEOPI- 

 THECUS. 



The second family, or the insectivorous ones, are 

 almost, if not altogether, nocturnal animals which live 

 in and often under the ground ; and most of those 

 which inhabit cold countries, hybernate or pass the 

 winter in a lethargic state. They feed chiefly upon 

 insects and other small ground animals, and thus 

 their teeth in the posterior part of the jaws are of the 

 insectivorous character. The nature of their food 

 renders it necessary that they should hybernate 

 during the inclement season ; because at that time 

 the insects of such countries are gone, and the other 

 ground animals have plunged to a considerable depth 

 below the surface. Those which dig habitually in the 

 ground are furnished with a keel upon the sternum in 

 the same manner as the bats : they are also all pro- 

 vided with clavicles, so that the cross motions of 

 their fore legs are powerful in proportion to their 

 size ; the hind ones, on the other hand, are often 

 feeble, and what with the feebleness of these, and the 

 cross motion of the anterior ones, they are very help- 

 less upon the ground, and may be said to crawl rather 

 than to walk. The whole of them are plantigrade, or 

 apply the entire sole of the foot to the ground in 

 walking ; and the greater number of them scarcely 

 raise the under part of the body clear of it. They 

 admit of subdivision into two sections, which depend 

 chiefly upon the form of the teeth. The one section 

 have a slight approximation to the rodentia, only 

 they have still the three kinds of teeth which belong 

 to the whole of the carnassiers. Their two front 

 incisives are their largest teeth ; but these are conical 

 and pointed, instead of being chissels, like the front 

 teeth of the true rodentia. The other section have 

 long canines, and very short incisive teeth ; but after 

 all, except in the most powerful teeth being at the 

 very front of the mouth in the one section, and a 

 little farther back in the other, there is very little 

 difference of character between them. The hedge- 

 hogs, the shrews, the musk ruts, the golden rnole of 

 Southern Africa, and a few other.*, belong to this sec- 

 tion. The moles, properly so called, the star-nosed 

 mole, and the water shrew of Canada, belong to the 

 section with short incisives and long canines. The 

 whole are very obscure animals in their habits ; and 

 though they lead very laborious lives they are well 

 adapted for their labour. It is probable that of these, 

 and of all the other small ground mammalia, which live 

 in obscurity, and seek their prey either during the 

 night, or altogether under ground, there are many 

 species besides those which are at present known to 

 naturalists. 



CAKNIVORA. These animals form the third and 

 most characteristic family of the order, though there 

 is considerable diversity in their forms and their 

 modes of life. There is a progress traceable to 



them all the way from the quadrumana, though 

 the habits of the animal are so very different. 

 The quadrumana, and also the cheiroptera, have ' 

 perfect clavicles, and the teats of the females are 

 situated on the breast. The insectivora have also 

 perfect clavicles ; but as pectoral teats would be 

 inconsistent with their action upon the ground the 

 females have these organs situated on the belly. In 

 the family of the carnivora there are rudimental cla- 

 vicles ; but none of them have perfect ones, and they 

 also have the teats on the belly ; and their hind feet 

 bear in general a greater resemblance to their fore 

 ones, both in form and in strength. Among the carni- 

 vora, the mouth, which is the instrument that principally 

 determines the kind of food, is uniform in the 

 number, general structure, and distribution of the 

 teeth, though in the form of the cheek teeth there * 

 are differences. The whole family are furnished 

 with four la)-ge and strong canine teeth, which stand 

 high above the others ; and between these there 

 are six front teeth in each jaw, the second one below 

 having its root or fang deeper in the jaw than the 

 others. The cheek teeth never have those sharp 

 points which characterise insectivorous teeth ; but 

 some have them furnished with flat bruising tubercles, 

 as well as sharp cutting edges. 



It is of some consequence to attend to the distinc- 

 tions of those cheek teeth, because the variations in 

 their form indicate very correctly the differences 

 of dispositions in the animals. Those next the 

 canines are not the largest, but they are furnished 

 with the sharpest cutting edges. It must be under- 

 stood, however, that their edges are not chissels for 

 simply dividing, but angularly pointed for tearing, or 

 rather, in this part of the mouth for cutting asunder 

 the flesh on which the animals feed. These are 

 called " false molars," that is, false grinders ; but the 

 name is not very descriptive of them, or indeed of 

 any teeth in the mouth of any of the carnassiers ; 

 for, as the jaws of their mouths have no lateral 

 play, the one upon the other, there can of course be 

 no grinding action in any part of the mouth. Grind- 

 ing is an operation required for reducing vegetable 

 matter to a pulp ; but animal matter is pulpy enough 

 without any such reduction, and all that it wants is 

 catching and tearing. 



Immediately behind these false molars there is, on 

 both sides of each jaw, a tooth, much larger than 

 either of them, and furnished with a tuberculous heel 

 on the inside, more or less perfect in the different spe- 

 cies. This tooth is usually called the great carnivo- 

 rous tooth ; and as it has the same kind of trenchant 

 edge on the outside as the false molars, and the heel 

 on the inside, it cuts and bruises at one and the same 

 time. There is a very beautiful adaptation in the 

 form of this tooth. It is the first w hich begins to pre- 

 pare the food for the stomach ; and as the bruising 

 part is on the inside, it bruises the part cut off, and 

 leaves that which is not cut, with the blood and other 

 juices entire, so that there is no loss or waste in the 

 food of the animal. The remaining teeth behind the 

 great carnivorous ones, are the molars properly so 

 called ; but even these are trenchant in proportion as 

 the owner subsists upon living prey. If any of them 

 have the crowns more abundant in tubercles, they are 

 placed farthest backward in the jaw, and they can 

 crush vegetable matter. The dog, for instance, as a 

 less decidedly carnivorous animal, has more of those 

 tuberculous teeth than the cat ; and the consequence 



