THE MAMMALIA— MAN AND BEASTS. 



37 



envelopes of the intestinal canal differ greatly among the several quadrupeds. There 

 are lateral omenta in some of the quadrupeds, which hybernate, such as the Polish and 

 Alpine Marmots, in addition to the usual omenta of other quadrupeds. They arise 

 from the loins, cover the sides of the abdomen, and advance neai-ly to its centre. 

 These processes of the Peritoneum become loaded with fat, about the period that 

 the animals remain torpid, and the fat is entirely expended during the time of their 

 hybernation. The use of these lateral omenta is sufficiently obvious ; yet it is very 

 sin"-ular that other species which sleep during the winter, and are nearly allied to 

 those just mentioned, such as the Garden Dormouse (Myoxus nitela) and the com- 

 mon Dormouse (Myoxus aveUanaritis) are destitute of thera. 



L'arine, retenue pendant quelque temps dans une vessie, sort, dans 

 les deux sexes, a un tres petit nombre d'exceptions pres, par les orifices 

 de la generation. 



In all the Mammalia [with the sole exception of the Monotremata] the 

 generation is essentially viviparous. Immediately after conception, the 

 foetus descends into the Womb, surrounded -nith its membranes, of which 

 the exterior is called the chorion, and the interior amnios. It is fixed to 

 the sides of this cavity by one or more folds of vessels called the placenta, 

 ■which establish the communication with the mother, from whom it 

 derives its nourishment, and probably also its oxygenation. In the 

 earlier periods of gestation, the foetus of the Mammalia possesses a small 

 vessel, analogous to that which contains the yolk of the Oviparous ani- 

 mals, and receiving supplies from the vessels of the mesentery in a simi- 

 lar manner. 



lis ont aussi une autre vessie exterieure, que Ton a nommee allantoide, 

 et qui communique avec celle de I'urine, par un canal appele I'ouraque. 



La conception exjge toujours un accouplement efiectif, oil le sperme 

 du male soit lance dans la matrice de la femelle. 



The young are nourished for some time after their birth by Milk, a 

 fluid peculiar to this class, and produced by Mammje, or Breasts. This 

 secretion commences at the moment of birth, and continues as long after- 

 wards as the young may require. It is from these Mammas that the class 

 has obtained its name of Mammiferes, or Mammalia. This being a cha- 

 racteristic peculiar to the animals composing this class, serves to dis- 

 tinguish them more precisely from the remaining classes than any other 

 external character. It remains, however, still doubtful whether the 

 Monotremata possess mammx or not. 



lyicckcl could find no traces of Mamm-ne in the male Ornythorynchus, but thought 

 he perceived them in the female. *' I detected, on the right side of the ahilominal 

 muscles," ho observes, " a small round mass, which at first bore the appearance of a 

 portion of intestine accidentally pushed into this situation. I was satisfied that this 

 gland was a true Jlamraa, an opinion which was more forcibly impressed upon my 

 mind from its structure and situation, from its marked development in the female, and 

 the want of it in the male, or at least its existence in so minute a degree as to have 

 hitherto eluded the closest examination." Oken and De Blainville asserted, a prion, 

 and without having ever examined a female Ornithorj-nchus, that its jVIammai must 

 exist, and would no doubt be discovered hereafter, on account of the very numerous 

 analogies which this animal presents to the other jMammalia. Sir Everard Home 

 describes the Mamma? of the Ornithor3'nohus in the Philosophical Transactions for 1802. 

 On the other hand, M. Gcoffroy considers that those organs are not real ATamma?, 

 but are analogous only to the lateral glands of the Muscardin (Myoxus avellanariiis.) 

 Again, tlie Ornithorynchus is either oviparous or ovo-viviparous, which properties are 

 always connected with the absence of Mamma:, and its bill evidently appears unfitted 

 for sucking; so that, upon the whole, it must still be considered as doubtful whether 

 these organs really perform the functions of Mammse. 



Although the !\!amma; are always found, with the above exception, in the females, 

 yet the males of many species are destitute of them, as the Hamster (Cricetus vul- 

 garis), and the Lemur mongoz, while in some others, as the Horse, they are found in 

 an unusual situation. The Maramre are frequently less numerous in the male than in 

 the female. Milk has often been secreted in the breasts of Men, as well as of other 

 male animals, such as the Goat, Ox, Dog, Cat, and Hare. Blumenbach describes a 

 he-goat which it was necessary to milk every other day for the space of a year. It is 

 very common to find milk in the breasts of newly-born children of both sexes; and 

 the same circumstance has likewise been observed in the calf and foal. 



In the Cetacea and Marsupialia the Mamma; do not project so as to form udders or 

 breasts, but they lie flat under the skin. In general the Mammje are very observable 

 only during the period of suckling, at which time they are largely distended with 

 milk, except in those animals having them placed upon the chest, when they possess 

 that graceful and delicate form observable in the human female of the Caucasian race 

 during the bloom of youth. It is very difficult to discover them in the iMarsupial ani- 

 mals, except at the period when the young are actually contained in the abdominal 

 pouch of the female. The number, as well as the position of the Mammce, varies 

 greatly in different animals. It would appear that there are frequently twice as many 

 teats as the number of young usually produced by each animal. Yet this rule is not 

 without several exceptions, among which may be included the Guinea-pi"- (^Cavia 

 cohaia), and the Domestic Sow. Indeed it is among the domesticated races that 

 these exceptions are chiefly found. Thus, according to Buffon, the marams of the 

 Sow vary from ten to twelve ; of the Cow from four to six ; of the Rat from eight to 

 ten. The Mare and Ewe may have from two to four, while the Ferret sometimes 

 has three on the right side, and four on the left. From these examples we may 

 readily perceive that no fixed law is observed in the number of the mammje. 

 10 



DIVISION OF THE CLASS MAMMALIA INTO NINE ORDERS. 



1. Bimaria — 2. Quadrumana — 3. Carnassiers — 4. liodentia — 5. Edentata — 

 6. Marsupialia — 7. Pachydermata — 8. Ruminantia — 9. Cetacea. 



Those variable characters, which establish the essential differences of the 

 Mammalia among themselves, are derived jointly from the organs of touch 

 and from those of mastication. The forms of the hands or feet chiefly 

 determine the degree of their agility and dexterity, while those of their 

 teeth not only correspond to the nature of their aliments, but draw along 

 with them innumerable other distinctions, relative to the digestive organs, 

 and even to the intellectual functions. 



The degree of perfection in the organ of touch is estimated by the 

 number of the fingers, their capability of motion, and the extent in which 

 their extremities are enveloped in a nail or hoof. 



A Hoof which entirely surrounds that extremity of the finger nearest 

 to the ground, blunts its sense of touch, and renders it incapable of 

 gi-asping an object. 



The opposite character is found in the Nail, composed of a single 

 layer, which covers the one side only of the extremity, and leaves to the 

 other the utmost sensibility of touch. 



The nature of their ordinary food is determined by the form of the 

 Molar or Cheek Teeth, and this always corresponds to the mode in 

 which the jaws are articulated. In order to cut flesh, the Molars must 

 be serrated, or saw-like, and the jaws united in the manner of scissors, 

 which can only open and shut. On the contrary, in order to crush 

 grains, it is necessary that they should have Molars with flat crowns, 

 and jaws capable of moving horizontally. It is also requisite that the 

 crown of these teeth should possess that kind of inequality which the 

 millstone acquires, that its substance should be of different degrees of 

 hardness, and that some of its parts should wear away more rapidly than 

 others. 



All animals with Hoofs [thence called Ungulated] must of necessity 

 be herbivorous, that is, possessed of Molar teeth with flat crowns, because 

 the structure of their feet prevents them from seizing a living prey. 



It is difltrent with those animals said to be Unguiculated, from their 

 possessing Nails. They are susceptible of several varieties, and may 

 partake of diflferent species of food; but they differ still more from each 

 other in the extent of motion possessed by the fingers, and the delicacy 

 of their touch. There is one characteristic which exercises a mighty 

 influence on the degree of their address and means of industry — that is, 

 the power of opposing the thumb to the other fingers, for the purpose of 

 seizing small objects, which constitutes it a Hand, properly so called. It 

 is in Man, whose fore-extremity is entirely free, and capable of being 

 eniploj'ed in seizing, grasping, or holding, that this power reaches its 

 limit of perfection. 



These different combinations, which determine rigorously the nature 

 of the different Mammalia, have given rise to their subdivision into the 

 following orders:^ 



the nNGUICULATED MAMMALIA. 



1. BiMANA. — Man alone possesses hands solely at his fore-extremities, 

 and at the same time is privileged in many other respects, so as to entitle 

 him to the first place among the unguiculated animals; his lower extre- 

 mities alone support his body in a vertical position. 



2. QuADROMANA. — Tile order next to Man possesses hands at all the 

 four extremities. 



3. Carnassiers. — The third order has not the thumb free and oppos- 

 able to the other anterior extremities. 



All the animals of the above orders possess three kinds of teeth, 

 namely, Molars, Canines, and Incisors. 



4. RoDENTiA. — The fourth order differs but slightly in the structure 

 of the fingers from the Carnassiers, but it wants the Canine Teeth, and 

 the Incisors are disposed in front for the pecub'ar kind of mastication, 

 termed Gnawing. 



5. Edentata. — Next follow those animals having the fingers very 

 much confined, and deeply sunk into large nails, which are often very 

 crooked. They also have the imperfection of wanting Incisors. Some 

 also want the Canines, and others have no teeth at all. 



6. Marsupialia. — This distribution of the Unguiculated animals would 

 have been perfect, and might form a chain of some regularity, if New 

 Holland [and America] had not furnished us with a small collateral chain, 

 composed of animals with Pouches. All these genera resemble each 

 other in the whole character of their organization, yet some of them 

 correspond to the Carnassiers by the structure of their teeth, and the 



