al study the more firmly upon our the study of a brief exposition, the natural ar anal farm sufficiently distinct and speScals of rs labiogical study a matter of easy torns more familiar as a being foreign to the ingrat, its history, like that of every other athervise must be investigated along the lines WE HAVE ST mit av The question "What is it?" is answered by morphology and a inge number of very interesting replies would be found amongst the anses to the questions of the science of structure. We should this be miarmed, as a primary fact of kangaroo history, 2x II Ma, backboned animal; that it agrees in the genen type of its body with all fishes, replies, birds, and quadrupeds; and we should, moreover, speedly discover by even a cursory anatomical examination that à belongs to the quadruped class, and presents essentially the same general characteristics which all quadru peds, from the while upwards to the lion, dog, rat, sheep, ape, and man, agree in possessing. But the more personal history of our kangaroo would show wide differences in structure from the organisation of ordinary quadrupeds. We should be struck by the low type of its brain, as compared with the brain of ordinary quadrupeds. We should note two curious bones unknown in common animals, and which arise from the front of the kangaroo's haunch-bones: these being the so-called "marsupial bones," on which the "pouch" these animals possess is supported; whilst in connection with this fact we should also discover that the young kangaroo is born in an immature condition, that it is thereafter transferred to the pouch of its mother, and that it exists therein for many days after birth, being duly nourished by the secretion of the milk-glands which open into the pouch. We might also note that the kangaroos, as every visitor to the Zoolo

gical Gardens knows, possess hind limbs which are developed out of all proportion to the fore legs. In its resting posture it sits upon a kind of tripod, or three-legged stool, formed by the tail and two hind limbs; and when the skeleton of the hind limb is examined, we find, further, that the great apparent length of the foot is in reality due to the elongation of the animal's instep bones. The foot, we may lastly note, possesses four toes, whereof two are very large and conspicuous, and two (placed to the inner side of the other toes) are very small, and united together by a fold of skin. There is no great-toe in the kangaroo; and the two large toes forming the bulk of the animal' foot are the fourth and fifth toes: the two small and rudimentary toes corresponding to the second and third toes in ourselves.

Thus much a brief study of " anatomy" would teach us about the kangaroo. Of its development, nothing need be said beyond noting the fact that it is formed and fashioned after the manner, firstly, of all vertebrates in general, and, secondly, of all other quadrupeds in particular. Kangaroo development stops short, so to speak, at a lower level than the development of such an animal as a dog, and at a considerably lower level than that of an ape or a man. But, if any proof of the exact nature of the kangaroo were wanting, such facts as those elucidated by its development would at once and indisputably settle its relationship to ourselves, as a low member of our own great class.

Next as to its "classification." What, it may be asked, is the kangaroo's place in nature? As the claims of structure settled the place and position of whale and fish in the animal series, so the morphology of the kangaroo allocates to it a situation in the quadruped class. The structure of many other animals is found to present a striking likeness to that of the kangaroo. The opossums, the wombats, the native "bears" and "hyænas" of Australian colonists, the kangaroo-rats, the phalangers, the bandicoots, and allied forms-all, with the exception of the opossums, confined to the Australian province-exhibit evident affinities to kangaroo structure. Relying upon structure-and development would be found to strengthen the evidence of morphology-we should place these animals along with the kangaroo in a special order of quadrupeds to which we give the name of Marsupials, or "pouched" animals. These animals would agree with the kangaroo not merely in lowness of brain structure, in the possession of the curious "marsupial bones," in the general arrangement and even special form of internal organs, and in the peculiar shape of the lower jaw, but also in the matter of the foot structure. Very striking is it to observe the prevalence of

the one type in the feet of this varied assortment of quadrupeds. "How curious it is," says Mr. Carvin, "that the hind feet of the kangaroo, which are so well itted for bounding over the open plains— those of the climbing, leaf-eating koala, equally well fitted for grasping the branches of trees-those of the ground-dwelling, insector root-eating bandicccts-and those of some other Australian marsupials should all be constructed on the same extraordinary type, namely, with the bones of the second and third digits extremely slender and enveloped within the same skin, so that they appear like a single toe furnished with two claws. Notwithstanding this similarity of pattern, it is obvious that the hind feet of these several animals are used for as widely different purposes as it is possible to conceive. The case is rendered all the more striking by the American opossums, which follow nearly the same habits of life, having feet constructed on the ordinary plan."

The science of structure thus settles the questions which naturally arise respecting the relationships of the kangaroo, by uniting it in classification with those forms which truly resemble it in structure. So also with its physiology. The second question, “How does it live?" would be answered in an exact fashion by the investigation of the life-processes of the animal, and by the knowledge which physiology would bring to bear upon the manner in which kangaroo existence is divided, like that of all other animals, between supporting its frame, increasing its race, and maintaining relations with the world around.

The question, "Where is it found?" involves in its reply, in the case of the kangaroo, a large number of highly interesting and instructive considerations. Kangaroos are found in Australia and adjacent islands alone. Why are they limited to this region of the earth's surface? and why, to put this question more generally, has Australia no native quadrupeds other than these marsupials and their poor relations?—for it need hardly be added, that the horse, cow, sheep, and allied animals are all of recent introduction by the hand of enterprising, colonising man. Looking at a zoological map of the world—a chart prepared solely with reference to the distribution of animal life— we should observe that the animals peculiar to Australia stop short on one side of a line called "Wallace's Line," which passes in one part of its course between the little islands of Bali and Lombok in the Eastern Archipelago. The straits of Lombok are about fifteen miles in width, yet that narrow sea divides the land of marsupials-Australia and adjacent islands-from other lands and islands in which no marsupials are found. Why, then, should the kangaroos and their marsupial kith and kin

stop short at "Wallace's Line?" The answer to this query involves considerations which extend over the whole domain of life-science. The briefest possible explanation of the kangaroos' distribution must therefore suffice for our present purpose. Let us go back in imagination to that far-back time in the history of our earth when the Triassic rocks were being formed. That period existed ages before the Chalk in point of time. It was the period, moreover, when the first quadrupeds appeared on the earth's surface; these primitive animals being wholly of marsupial kind, and entirely of the type of which our kangaroos and other Australian mammals are the existing representatives. Not a single higher mammal thus graced the Triassic forests; no elephants roamed in Triassic jungles; the plains of these early times were unenlivened by the agile deer, or by the grace of the antelope herds; no carnivora roamed about to slay and devour the weaker races; and the humblest quadrupeds were lords of animal creation, and represented in themselves the fulness of the mammalian life which the later ages were destined to see.

Over the whole land surfaces then in existence these low marsupial quadrupeds of the Trias in due course spread. In Britain, on the Continent, in the New World, the fossil remains of these early Triassic quadrupeds are found; the best known of them being represented most nearly by the little "banded ant-eater" (Myrmecobius) living in Australia to-day. In the Triassic period, also, Australia obtained its marsupials. For that island-continent was then part of the Asiatic or Palearctic mainland, and the connecting land was not then broken up into the islands of the Eastern Archipelago of to-day.

The next phase in the drama of Australian quadruped-life shows us that at the close of the Triassic and of the succeeding Oolitic periods, that land became disjointed from the mainland. Geological change made Australia the island-continent we see it to-day. And what of its quadrupeds? These early marsupials, left to themselves, shut off from all possible invasion by and competition with higher and later quadrupeds, flourished and grew apace in the Australian land. Elsewhere, and in the rest of the world, the early marsupials were distanced in the "struggle for existence" which ensued on the evolution of higher types of life. Elsewhere than in Australia they were killed off, and at the close of the Oolite age (or that immediately succeeding the Trias) hardly a remnant of the great marsupial life of these two periods was left to bear witness to the first beginnings of mammals on the earth. In Australia how different was, and still is, the quadruped-life. In the recent bone-caves of Australia, we meet

with the remains of giant marsupials, compared with which the largest kangaroo of to-day appears a pigmy form. These are the lineal descendants of the first mammalian population which Australia obtained from the Triassic period. Thus left unopposed, until the advent of the colonists, the marsupials have lived and flourished in Australia, which still retains the main features of its Triassic and Oolitic life. For in its seas swims the Port Jackson shark, elsewhere known only by fossil representatives from the Oolitic rocks. In its rivers lives the curious fish Ceratodus, whose teeth occur fossil in Triassic and Oolitic formations. The cycads and araucarias, representing a typical plant vegetation of the Oolitic times, still flourish in Australian soil, though elsewhere scanty or non-existent ; and even the shell-fish on the shores of Australia belong to types which flourished in our own Oolitic seas, but which have since practically died out over the world, save the Australian shores. Thus, Australian life at large is the survival of the general life which prevailed over the world in the Trias and Oolitic periods; and the history of the kangaroo points out clearly enough that only on the theory of evolution having given rise to new species from the ancient and original Triassic stock, can we account for the persistence in a corner of our existing world, of the otherwise lost and extinct population of the first quadrupeds.

Lastly, the opossums-which, as a family of marsupials, we should have expected to find in Australia-are discovered, as already remarked, in America. "How came they, then, to inhabit the New World?" is a question worth answering, along with that which inquires into the distribution of the kangaroo. The opossums represent a family which never entered Australia, to begin with. They were plentifully existent in Europe and elsewhere in the Oolitic period, and even nearer our own day—namely, in the Eocene and Miocene formations-the opossums lived in the Old World. These facts are accurately told us by the history of their fossil remains. Thence their range extended to the New World; and, when a subsequent irruption of higher quadrupeds killed off the opossum-race elsewhere, these animals continued to flourish and grow in the New World, presumably because the struggle for existence was less severe in the latter region. As the kangaroos are survivals of a quadruped-life, world-wide in Triassic and Oolitic times, so the opossums are survivals in their turn of possibly later forms than the Australian animals. Finding in the New World, to which they migrated, a suitable home, the opossums, distanced in the competition in the Old World, and now extinct therein, have