MAMMAI/IA. 757 MAMMALIA. ordinary A-ariety of adaptations, and are aflected by and react upon all conditions of existence. Where room is almost unlimited and food abun- dant and perennial, great size is attained, as in the whales, which reach a length of 100 feet and corresponding bulk and weight ; elephants, which may weigh five tons : and the great grazer.-,, which often exist in vast herds; and. on the other hand, many forms, adapted to a very limited range of vital conditions, are minute in size. Between these extremes is a wide range of size, power, and adaptability to climate and food, so that hardly any organic thing, alive or dead, escapes being eaten by some mammal. On the other hand, they themselves form the food of each other, and of all other flesh-eating ci'eatures in a greater or less degree. In respect to food the mammals fall into two great categories — vege- table-feeders and flesh-eaters, with a few forms tliat may be omnivorous. The vegetable-feeders (Edentata, Sirenia, Ungulata, and Kodentia) are likely either to be of large size or exceedingly numerous in individuals, or both. They are ill provided with weapons of defense or oll'ense; trust for safety to powers of swift escape or of skillful hiding; and as a rule are sluggish and inferior in brain power. It is their part (from the present point of view) to elaborate from the semi-crude nutriment in vegetation the more compact and highly nutritious substance called llesh. which is to be used by their superiors in organization ; their mission in life is to provide a prepared food for the carnivores. These quali- ties also make them useful to man, and it is from this class that he derives almost everything in the way of food, oil, clothing, and service which animals contribute to his welfare. The flesh-eaters include two alierrant groups — the aerial insect-catching bats, and the marine Cetacea, the latter, by the peculiarities of their respective habitats and the restricted character of their food, having a special place and special functions. A few forms of antiquated organiza- tion, small size, much restricted range, and in- ferior abilities generally feed upon insects alone I Insectivora ) or in large part (Primates), and share the perils of the vegetable-eaters. The greater part of the flesh-eaters, however, form a group (the order Carnivora) which in com- plexity of organization, power, resourcefulness, and general ability stands at the head of the animal kingdom. Whatever may have been the case with the extinct and unknoHm ancestry of man, there is no question that the cats and weasels and their kin are far superior even to the anthropoid apes in those powers and abilities which make for mastery in the animal world. These remarks have applied mainly to the eutherian mammals ; but a similar divi- sion is foiuid in the Jletatheria (marsupials) ; and this circumstance is an argiunent in favor of the theory of the independent origin and de- velopment of that group, and opposed to the view which regards it as a stage in the evolution of the mammalian stock. In both groups the vegetable-feeders are numerous, large, timid, comparatively defenseless, and without either means or desire for aggression, except as between males of the same species. They get their food with comparatively little exertion, and. except in the case of certain rodents, have had occasion to develop few instincts or mental faculties. Their whole life is passed in an effort to escape by fleetness or to find and keep a hiding place; and here mainly have been developed such de- vices as illustrate protective coloration and mimicry (q.v.) in this branch of the animal kingdom. The carnivores, on the other hand, have been compelled to work day by day for their subsist- ence. They have been obliged to overcome by strategj' and cunning, as well as bj- force, the greater size and speed of many of the flesh-eaters, and to oppose quickness, patience, and wit to the numberless defensive and protective abilities and devices of the smaller and more secretive ani- mals; and they have been forced to do this in close and constant competition with other carni- vores. Hence the apparatus of claws and car- nassial teeth, developing the canines rather than the incisors; the tireless, efficient muscles; the capability of sudden tremendous exertion and equally of great endurance; the vigilance, cour- age, subtlety, and resourcefulness which char- acterize cats, wolves, foxes, dasyures, weasels. and lesser beasts of prey. Develojjed by such a history of contest and courage, it is not strange that ferocity and self-reliance should characterize the disposition of the cai'nivores. nor that man- kind in its progress toward peace has found it- self in competition with them for the possession of the best of their prey — the edible herbivores — and also at war with them for its own defense. It is wonderful, however, that man should have derived from this class such friends and helpers as the cat and dog, and no stronger evidence could be adduced in favor of the proposition that the Carnivora represent the highest animal men- tal development than the traetability of the dog and cat, and the mental qualities they have ex- hibited under man's control and tutelage. C'L-iSSiFicATioN. Linnajus (17G0) divided the mammals into seven orders: Cete, Bellufe, Pecora, Glires, Ferse. Bruta. Primates. Of these orders the Cete, Glires, and perhaps Belluie and Pecora were natural groups quite similar to some of our modern orders. But under Ferse were grouped opossums, moles, hedgehogs, weasels, bears, dogs, eats, and seals ; evidently the use of animal food was the principal character common to such an assembly. Under Bruta. moreover, such widely dift'erent animals as elephants, anteaters, and sloths were united. Finally, in the Primates, not only were man and monkeys associated, but even the bats were included. Cuvier reformed this arrangement as a result of extensive anatomical investigations. He recognized nine orders of mammals, as follows: Bimana, Quadrumana, Carnivora. Marsupialia, Rodentia, Edentata, Pachydermata, Ruminantia, Cetacea. There is little that is really unnatural in this arrange- ment, and it remained in popular use down to the very close of the nineteenth century. Cuvier regarded man's intellectual ([ualities as such as to rank him in an order apart from the monkeys, a backward step from Linnipus's arrangement. His Bimana and Quadrumana are now fused as Linna'us's 'Primates.' and Cuvier's Pachydermata and Ruminantia are likewise united: but his other orders stand substantially as made, .fter the doctrine of organic evolution was generally accepted, the tendency was toward a far more elaborate and complex classification among both animals and plants. As a result, some of the proposed classifications of mammals suggested no less than twenty-five orders; but the pendulum
