“Intelligence is a conservative principle, and will always direct effort and use into lines which will be beneficial to its possessor. Here we have the source of the fittest—i.e., addition of parts by increase and location of growth-force—directed by the influence of various kinds of compulsion in the lower and intelligent option among higher animals. Thus intelligent choice, taking advantage of the successive evolution of physical conditions, may be regarded as the originator of the fittest, while natural selection is the tribunal to which all results of accelerated growth are submitted. This preserves or destroys them, and determines the new points of departure on which accelerated growth shall build.”

I think Professor Cope goes much too far in assuming that the intelligence of animals always directs effort and use into lines which are beneficial to its possessor; for, if such were the case, the intelligence of animals would surpass that of mankind. A little reflection will, however, show that the action of animal intelligence, even where the intelligence is of a limited order, must necessarily largely influence the development of the body, although such influence, instead of being conscious choice, must be exercised unknown to the animal itself. The animal uses its intelligence to supply its daily wants, and in doing so it is brought within the sphere of new physical surroundings, which modify its bodily structure. By way of illustration, let me point to the New Zealand kokako, or crow. Now, the blue-wattled crow is confined to the North Island, while the orange-wattled crow is restricted to the South. Ornithologists class these two crows as distinct species. No naturalist would contend that these two members of the crow family had been independently evolved in the North and the South Island—obviously one of them is a modification of the other. Impelled by lack of food or perhaps other circumstances, the intelligence of the ancestors of one of these crows led them to migrate from the North to the South Island, or vice versd, and the change of climate and diet, with possibly other alterations in the environment, led to the production of a new species, or what we, for convenience sake, call a new species.

Individual animals, like human individuals, and races of animals, like races of mankind, display marked peculiarities of mental character; and in dealing with domesticated animals man has often taken advantage of these idiosyncracies, and, in so doing, has modified the physical structure of various-animal breeds. Thus, breeds of hounds of fierce disposition and prone to the chase, breeds of spaniels of affectionate temper and ways, have been created; while the collie, quick and watchful, has been taught to tend flocks of sheep and

herds of cattle. The physical structure of each breed has become modified to suit its place in life, and to better adapt it to fulfil what its mental capacity enables it to perform.

The chief occupations of an aminal are to provide itself with the means of subsistence, sometimes with shelter, to defend itself against the attacks of enemies, and to multiply its kind. Those animals which are gifted with the most intelligence, whose appetencies and desires are the keenest, are the most likely to succeed in the struggle for existence. Not, indeed, always so. A fatal and wide-spreading disease like the rinderpest may doom millions to death; it may spare less intelligent animals, possessing bodily peculiarities fitting them to resist the disease, and carry off individuals more intelligent, but with constitutions prone to the disease; a great catastrophe of nature, like a flood or volcanic eruption, an extraordinary period of frost or of hot weather, may destroy vast numbers, and neither superior intelligence nor superior strength of body may avail to save the animal's life. Leaving out of account, however, such special causes of mortality, it is plain that the individual animal of any species which is gifted with an active intelligence will be more likely to hold its own than the individual whose mind is sluggish. The cat which discomposes the household by its thievish propensities would, in the wild state, manage to provide itself with an excellent living where the well-behaved tabby would starve. The bird of any species which best conceals its nest from the enemies which prey on its eggs and young, and most carefully nurtures its young, will be more likely to leave progeny surviving it than another bird of the same species whose less active intelligence make it less successful in the performance of these parental offices.

It is to the varying mental characteristics of animals that the dispersal of animal races and the multiplication of species is largely due. Professor Karl Semper has shown how certain species of crustaceans can be transmuted into one another according to the saltness of the water in which they live. He proved by experiment that a small crustacean named Artemia milhausenii, which lives in salt-water, can be transformed into an apparently entirely different crustacean called Branchipus stagnalis, which inhabits fresh water, the two animals being so different in outward aspect that naturalists had classed them as belonging to different genera. Now, in nature either Artemia milhausenii must have migrated from fresh water to salt, or Branchipus stagnalis from salt water to fresh, and in either case it must have been impelled by its own mental desires to seek the change of habitat which has produced so marked an effect upon its bodily structure. There

is nothing to lead us to suppose that this is an isolated instance. Indeed, many fresh-water fish are obviously modifications of marine forms. Heilprin writes, “Of so little importance does a change of medium appear to be in many cases that it is frequently very difficult, or impossible, to indicate whether a given group of fishes is more properly of a marine or fresh-water type. The numerous instances where certain species of a genus are of one habit and other species of the same genus of the opposite habit render the determination of this question still more difficult.”

Some animals are of a more restless disposition than others. We find such to be the case amongst domesticated races. Some cows are habitual fence-breakers, and special means have to be adopted to keep them in enclosed fields; while other cows, so long as a field contains sufficient pasture for their wants, will remain contentedly in it. Even a dull-witted creature like the domesticated sheep exhibits similar idiosyncracies. I knew a farmer who owned a small flock of sheep which was so addicted to straying that the sheep actually learned to leap over gorse fences of considerable height. Wild animals doubtless exhibit similar traits of character; and when, impelled by a desire for change, a herd of animals moves on to a fresh region, the effect may be that it will permanently take up its abode in a new country, where its changed environment will cause it to ultimately develope into a new species. Even if it leaves its original habitat owing to lack of food or persecution by enemies, the intelligence of the animal nevertheless comes into play by leading it to migrate and choosing the direction. But for the exercise of intelligence the animal would fail to seek food in fresh regions or to retreat thither from its enemies; and it is easy to perceive that a particular herd of animals of quicker intelligence than another herd might escape dangers which would prove fatal to the latter. The extraordinarily large herds of antelopes which, until recently, roamed in South Africa could never have existed in a country so abounding in savage beasts of prey but for the exercise of ceaseless vigilance on the part of the members of those herds, and any particular herd which relaxed its vigilance must speedily have disappeared. The alertness of the antelope's disposition finds its outward expression in the physical structure of the animal; a vigilant mind is aided by the power of rapid flight, while the power of rapid flight would be of little use divorced from an active intelligence.

The circumstance that an animal of feeble frame is subject to the frequent attacks of a beast of prey serves to keep the intelligence of both up to the highest pitch; to make the assailant cautious and cunning, and the attacked vigilant and

active, the constant strain in each case tending to develope and strengthen those physical characteristics which best tend to the animal's preservation. There is thus an unceasing reciprocal action going on between the intelligence of animals which either associate together or are frequently brought into contact as enemies.

It is the intelligence of animals which has led them to associate together in communities, often very large, by means of which they afford mutual aid against enemies, and also enjoy social intercourse. The latter, indeed, is probably quite as much the cause of the formation of animal comunities as the former. The American bison, or buffalo, formerly roamed North America in herds containing millions, yet it was itself the strongest and fiercest animal on the continent, and even had it required to combine for purposes of defence much smaller herds would have sufficed for the purpose. But whatever may have been the original cause of the formation of these vast herds, it was the mental principle in the bison which brought them about, and these irresistible combinations exercised a vast influence over the destiny of the bison, and might have endured for untold ages but for the advent of civilised man, armed with his deadly weapons of destruction, against which the bison's intelligence was powerless. Another animal formerly found in large numbers in North America—the beaver—also illustrates my argument. The beaver's social disposition and remarkable engineering capabilities have resulted in its bodily structure becoming eminently fitted for their exercise.

Animals which have a wide range will always be found to be intelligent. The sagacious elephant inhabits a large part of Africa, Southern Asia, and the Malay Archipelago, while extinct species of the race were dispersed over a much more extensive area of the earth's surface. The jaguar is one of the most intelligent of the larger beasts of prey, and its range in America extends from Patagonia to Texas. According to Wallace (“Travels to the Amazons,” p. 316), “The jaguar, say the Indians, is the most cunning animal in the forest; he can imitate the voice of almost every bird and animal so exactly as to draw them towards him; he fishes in the rivers, lashing the water with his tail to imitate falling fruit, and when the fish approach hooks them up with his claws. He catches and eats turtles, and I have myself found the unbroken shells, which he has cleaned completely out with his paws; he even attacks the cow-fish in its own element, and an eye-witness assured me he had watched one dragging out of the water this bulky animal, weighing as much as a large ox.” Taking the elephant and jaguar as types of intelligent animals of the larger kind, the rat, and especially the Norway

rat, may be taken as illustrative of the smaller quadrupeds. The mental faculties of the Norway rat are of a high order, and this animal has now established itself over a considerable portion of the civilised world. It is commonly asserted that it owes this extensive range to man's introduction, but certainly man has not purposely imported the rat into new countries; the rat, impelled by its own mental vigour and enterprising disposition, has followed in man's wake, and established itself in regions where man certainly did not want its presence. The rat possesses a great capacity for adapting itself to circumstances, and will, as occasion arises, eat fish, flesh, or grain, while the records of the New Zealand Institute show that in this colony it has developed a taste for shellfish.

From amongst the birds we may take an almost cosmopolitan family, the crows, which are distinguished for their intelligence; in fact, one genus of the family seems to hold something like Courts of justice for the punishment of offenders; and these birds likewise display great capacity for varying their diet, which must be of material assistance to them in the struggle for life, some feeding on fruit, some on insects, and others on carrion.

If we turn to the denizens of the ocean, the Cephalopods, which are the most intelligent of the molluscs, have a worldwide distribution, while, in point of geological time, their remains can be traced as far back as the Cambrian formation.

The sudden incursion of many varieties of foreign animals into New Zealand would have furnished an interesting test of the power of the native fauna to meet the invasion but for the circumstance of its being accompanied by the arrival of large bodies of civilised men, whose wholesale destruction, not only of the indigenous animals but also of their food and shelter, is beyond the power of the native fauna to resist. Yet, were it not for the actual direct destruction of much of the native fauna by the colonists, the intelligence of quite a considerable number of our New Zealand birds is apparently sufficient to have enabled them to survive amid their changed surroundings and new competitors, although in reduced numbers. The kea, kaka, weka, parroquet, the different species of hawks and ducks, the kingfisher, tui, fantail, wax-eye, cuckoo, and swamp-hen, all seem able to hold their own against everything but the gun and other means used by men to destroy them. All of these birds are intelligent, and some highly so. The kea's suddenly developed carnivorous propensities, which have so often been commented upon, prove that it possesses an adaptable nature well fitted to cope with novel conditions of life. Mr. Green, in his work on “The High Alps of New Zealand,” gives his

own experiences of the kea's intelligence. While camped upon the lower slopes of Mount Cook he and his companions were troubled by three keas, one of which he finally managed to kill with the blow of a stick; and a second, which seemed curious about the fate of its companion, he also contrived to strike on the back, but without killing it. Mr. Green proceeds, “The wisdom of these keas was remarkably illustrated by the readiness with which they profited by this lesson concerning a new source of danger. Up to this time we had had no difficulty in approaching and shooting them with the gun; after this incident they never let us come within range. The size of this parrot's brain when compared with that of the ducks which we shot was a source of frequent comment as we prepared them for the pot, and the deficiency of brain-power in the ducks was demonstrated not only by dissection, but by the slowness with which they profited by the lessons of experience.” I do not, however, agree with Mr. Green's low estimate of the intelligence of our New Zealand ducks.

One of the most remarkable problems encountered by the student of nature is the cause of the disappearance of innumerable forms of animal life which once tenanted the globe. They culminate, in numbers and diversity of structure, at certain epochs, and then disappear from the world's life-history, sometimes suddenly (although the suddenness may be only apparent) and sometimes gradually. The dinosaurian reptiles, which formed such a conspicuous feature of the Mesozoic fauna, may be taken as an example. Judging from the fossil remains which have been exhumed in many countries, these huge and often strangely shaped creatures must at one time have ranged over a large portion of the land-surfaces of the Northern Hemisphere, and been very abundant. Many of them were of gigantic size, far surpassing in magnitude any land animal now existing. One, the Atlantosaurus, whose remains have been discovered in the Jurassic deposits of the Rocky Mountains, measured from 80 ft. to 100 ft. in length; others 50 ft., and so on. Their skeletons, too, are of the most massive description. It would seem as if no enemies outside of their own race could successfully assail such monsters, and that changed surroundings could make but little difference to them. Nevertheless, at the close of the Mesozoic period the dinosaurs vanished, one and all. What was the cause of their sudden effacement? Some inquirers have attributed it to the failure of a sufficient supply of food, but there is no actual evidence to support such a theory, and it seems inherently improbable. Most of the dinosaurians were vegetable-feeders, and the Tertiary period is marked by abundance of vegetation. Moreover,

looking at the reptilian nature of the dinosaurs, it is quite possible that, like many modern reptiles, they were slow digesters and of sluggish habit, and that the quantity of food which they consumed was not so great as their size would suggest. Nevertheless, the dinosaurs passed away. They proved unable to accommodate themselves to the changed environment, and why? I think the explanation is to be found in their low intelligence. The crania of these animals show that the brain-cases are small—a sure indication of limited intellect. Physically their frames may have been capable of adjustment to suit an altered environment, but the brain-power necessary to initiate the adjustment was lacking. They were unable to change their old habits of life.

The same cause will probably explain such apparent anomalies as the entire disappearance of the mammoth from Northern Asia, while its near congener, the elephant, still survives in the south of that continent, although the mammoth and the elephant were once contemporaries. Heilprin thus propounds the problem: “Both [i.e., both elephant and mammoth], as far as we are permitted to judge, appear to have been in harmony with their surroundings; vegetable feeders, they inhabited regions of sufficiently luxurious vegetation, the one provided with a shaggy coat of hair to protect it from the rigours of the frozen north, and the other, more nearly naked, suited to a home where little or no protection from climatic extremes was necessary. Both, again, were inhabitants of regions where a struggle against the attacks of savage carnivora was a part of their existence, and if any advantage favoured the one above the other in such internecine warfare it was on the side of the northern species.” But if we assume that the mammoth was less sagacious than the elephant, that it possessed a less flexible mind, a more sluggish disposition, less capacity for adapting its actions to changed circumstances, the mystery is explained, and we can understand how, as the environment was transformed with the passing ages, the mammoth disappeared while the elephant survived.

Viewed from a mental standpoint, the apt phrase “survival of the fittest” acquires a peculiar significance. It is impossible to discover the life-history of a species from its mental powers, or to form a just estimate of the part played by any particular animal in the long procession of life without taking into account the peculiar mental capacity of the species as well as of the individual animal. It may be, also, that what I will term the collective mind of a species exhausts its powers of adaptation in the course of time, and that it then refuses any longer to respond to the pressure of outward

stimuli. Experience teaches every man that his own mental capabilities are confined within certain limits, and while mankind has accumulated vast stores of knowledge by the acquisitions of successive generations, there is no reason to suppose that men possess greater mental capacity now than they did in the days of the ancient Greeks and Romans. We know, too, that nations once intellectually powerful have ceased to be so. Bain has striven to prove that the reasson why man's mental powers are limited is because the number of nervous elements by means of which the mind acts in the human body is necessarily limited; and whatever of truth there may be in this theory will apply also to the lower animals. There is an old age of the species as well as of the individual, and the time comes when the species can learn no more.

Before one species can be transformed into another, however gradual the transformation, there must at some stage be a new mental departure. Before the reptile could have been converted into a bird the reptile must have manifested bird-like desires. Before the ancestor of the ant could have taken the first step which ultimately led to the present social organization of this insect it must have manifested a desire and aptitude to live and labour in common with its fellows, and this desire and aptitude, gaining strength through long generations, has not only produced a complex social economy which is truly remarkable, but likewise resulted in the physical organization of the insect being, fundamentally altered to facilitate division of labour. The same observations apply to the honey-bee. In both cases we must ascribe the origin of the special physical development of the insect to its peculiar mental organization. It has often been urged as an argument against Darwin's theory of development that slight modifications of bodily structure could seldom be of any use to an animal, or serve to originate novel structures. No doubt this is true if we merely regard such modifications as of themselves assisting the animal in the struggle for existence, but if we view them as means whereby individuals with a slightly different mental character from the rest of the species can give vent to their idiosyncracies, such modifications assume a greater importance. They may be of no consequence in an animal of the ordinary mental capacity of its race, but of great importance to one possessing individuality of character.

The climbing-perch (Perca scandens), of Tranquebar, climbs the fan palm in search of certain crustaceans upon which it feeds. When climbing it suspends itself by its open gill-covers, deflects its tail laterally upwards, so as to bring to bear upon the bark some little spines with which its anal fin