MAMMALIA. 



645 



TOUCH is always more perfect in animals whose 

 fingers are more numerously developed, and which 

 art; least covered at their tips ; such as those pos- 

 sessing only a single nail protecting their upper 

 extremities, as in man, apes, and lemurs; sensation 

 in the toes of such as are covered with hoofs, on the 

 contrary, is extremely blunted. 



CLOTHING. Animals are provided by nature with 

 a covering adapted to the, situation in which they are 

 placed. Living for the most part on the earth's sur- 

 face, the mammalia are exposed to the transitions of 

 heat and cold; the bodies of most of them are covered 

 with a coating of hair, varying in thickness. As their 

 habitation approaches the northern regions, it is more 

 dense, and thinner towards the equator. The ceta- 

 ceous animals which inhabit the sea, are totally 

 divested of hair. 



The essential characters of the mammalia are taken 

 from the number and structure of their teeth, and the 

 construction of their hands and feet. On the perfec- 

 tion of the organs of touch, the expertness of the 

 animal depends; and from their dentary formula may, 

 in a great measure, be deduced the nature of their 

 food and digestive functions. 



Animals which feed on flesh have three kinds of 

 teeth; incisors, or cutting teeth, pi. 52, f. 48, a; 

 canine, or tearing teeth, b; and molars, or grinding 

 teeth, c. Those which subsist entirely on animal 

 food, have all their teeth more acute than those 

 which live partly on other substances. Man is an 

 omnivorous animal, and with the structure of his 

 teeth we shall contrast those of the lion. Plate 52, 

 fig. 7, represents an incisory tooth of man ; fig. 10, 

 the incisor of a lion; fig. 8, canine of man; 11, 

 that of a lion ; fig. 9, the molar of man, and 12, that 

 of a lion. Fig. 16, represents the molar of the 

 Mastodon of America. Fig 1 . 15, are the molars of 

 the lower jaw of the Neotoma Floridana, an animal 

 which exists exclusively on grain and other vege- 

 table substances ; which is indicated from the con- 

 struction of these. If these are contrasted with those 

 of a highly carnivorous quadruped, the Viverra gra- 

 cilis, a striking difference will be observed, for, in 

 place of the flattened surface of those of the Neotoma, 

 the latter exhibit a sharp and irregular surface : fig. 

 25, represents the second molar of the upper jaw of 

 Viverra gracilis ; 26, second molar of the under jaw, 

 and 27, the molars of the under jaw. The front view 

 of the teeth of the Viverra or Musanga are given 

 at 28, which show the strongly developed canines. 



Animals of the Rodent order, have but two kinds 

 of teeth, and they live chiefly on grain, nuts, and the 

 bark of trees. Their cutting teeth or incisors, are 

 formed very differently from those of most other 

 animals. Plate 52, fig. 18, is an incisory tooth of the 

 upper jaw of the Isodan pilorides, viewed exteriorly; 

 fig. 20, an interior view of the same, and 19 an an- 

 terior view. The entire construction of the jaws of 

 these are very different from those which live upon 

 flesh, and other food, as will be seen by comparing 

 the jaws, figs. 14 and 17, with fig. 21, which is the 

 cranium of the Mangusta Javanica, an animal which 

 is highly carnivorous, and represented at plate 52, 

 fig- 21. 



The method of Cuvier is adhered to, in the generic 

 characters which we have given in the following 

 classification of the mammalia, wherein the dental 

 formula, and construction of the extremities form the 

 principal generic distinction. The arrangement of 

 the figures is intended to represent the upper and 

 under jaw. For instance, in man, the incisory or 

 cutting teeth, are placed in the centre of each jaw, 

 four above and four below, and are marked i ; the 

 canines, or sharp-pointed teeth, are next to these, 

 placed further back, that is, one on each side of the 



incisory teeth above and below, and are marked 

 j- +j beyond these, and further in the mouth, are 

 the molars or grinding teeth, five on each side 01 

 the canines above and below, marked \ J, making 

 a total of thirty-two teeth. The Chimpanzee, an 

 animal which stands next to man in point of organi- 

 zation, has a similar arrangement in the number and 

 kinds of teeth. 



Cuvier divides his class Mammalia into the fol- 

 lowing orders : 



I. BIMANA ; with two hands, of which Man is the 

 only species. He has three kinds of teeth. 



II. QUADRUMANA; animals with four hands, and 

 having three kinds of teeth. Monkeys, &c. 



III. CARNASSIERS. These have three kinds of 

 teeth, which are more or less of a carnivorous char- 

 acter. Thumb of the anterior extremities never 

 opposable to the other fingers or toes. It is divided 

 into four families Cheiroptera, or bats ; Insectivora, 

 or such animals as feed much on insects, as the 

 Hedgehog, &c. ; Carnivora, animals which subsist on 

 flesh; Cats, c.; Marsupialia, animals provided with 

 a pouch for the protection of their young after birth, 

 as the Kangaroo, &c. 



IV. RODENTIA, or Gnawers ; animals with two 

 large incisors in each jaw, separated from the molars 

 by a void space. The molars in most genera with 

 flat or riggled crowns, and in others blunt tubercles ; 

 Hares, Squirrels, &c. 



V. EDENTATA; generally destitute of teeth ; some 

 genera with molars only; their toes varying in num- 

 ber, and provided with large hoof-like nails. Ant- 

 eaters, &c. 



VI. PACHYDERMATA, or thick-skinned animals; 

 it includes all the hoofed quadrupeds, except the 

 ruminants. Horses, &c. 



VII. RUMINANTIA; animals which ruminate or chew 

 the cud, with cloven feet, and provided with four 

 stomachs. Deer, &c. 



VIII. CETACEA ; whales. 



Latreille and other naturalists have separated the 

 Cheiroptera from the order Carnassiers; and even 

 Cuvier himself proposed that the Marsupial animals 

 should be formed into a distinct order. 



The following arrangement has been adopted by 

 us : Order I. Bimana, II. Quadrumana, III. Cheir- 

 optera, IV. Ferae, V. Marsupialia, VI. Glires, VII. 

 Edentata, VIII. Pachydermata, IX. Ruminantia, X. 

 Cetacea. 



Cuvier and Latreille have placed the genus Orni- 

 thorynchus in the order Edentata, but this animal 

 possesses characters which will not apply to any of 

 the Cuvierian orders, and would properly make an 

 order of itself, consisting of one genus. 



Tlie mouth of the Ornithorynchus is formed like 

 the bill of a duck, resembling that of a shoveler or 

 other broad-billed species; pi. 52, fig. 49. The 

 internal edges of the under mandible, (which is nar- 

 rower than the upper), are serrated or channeled 

 with numerous striae, as in a duck's bill. The nostrils 

 are small and round, and are situated about a quarter 

 of an inch from the tip of the bill, and are about an 

 eighth of an inch distant from each other. The fore 

 feet, fig. 47, have five straight, strong, and sharp- 

 pointed toes, the two exterior ones somewhat shorter 

 than the middle three, a broad, fan-shaped web ex- 

 tends considerably beyond the claws. The hind feet, 

 fig. 31, are provided witli five other claws longer and 

 more curved than those of the fore feet; the exterior 

 toe and claw are considerably shorter than the other 

 four. The males have a long sharp spur, situated con- 

 siderably above the toes, through a small perforation of 

 which they eject a poisonous liquor. See OrnitAv- 

 rynchus. 



