others have overrated it. As to the Bible, and the results on it of modern criticism, the Church of Rome bas still her position to take up; and if ever she teaches anything authoritatively on the matter, we may be sure she will teach nothing that will be demonstrably at variance with fact. Her attitude, however, on this point, and with regard to the Old Testament especially, may reasonably cause some perplexity. As to her subsequent history, we shall doubtless discover in it many facts that seem to tell against her. But it will, I believe, be found that none of these facts are of such a nature as to absolutely give the lie to her claims; or if so, that they rest on insufficient evidence. Uninspired history, indeed, is much like the Bible. It may be read in many various and often contradictory ways, and, for it to convey any distinct impression to us on many points, we shall need an interpreter whose authority equals that of

the text.

For the present, however, putting the historical question aside, and looking simply on the world as it is, on science as it is, on our morality as it is, on other religions as they are, and on the Catholic religion as it professes to be, what I have tried to show is this: that the Catholic religion is a logical development of our natural moral sense, developed indeed under a special spiritual care, but essentially the same thing, with the same negations, the same assertions, the same positive truths, and the same impenetrable mysteries—the difference only being that what was always implied unconsciously is by it recognised and expressed consciously.

It is possible that we may see thus much, and yet feel ourselves unable to go further. Such an inability, however, will not detract from the truth of what I have been urging, nor from the utility of duly considering it. Any apology for Romanism is to many a very distasteful thing. But such petulant and vulgar prejudice as this should never be given way to. The Roman Church exists, and exists as a power in the world; and whether she be an enemy to be destroyed, or a saviour to be clung to, it is equally important that we should estimate her full strength. It is idle to waste our arguments and our sarcasm on Protestantism only. If we think that Christianity is false, and is doing an evil work in the world, let us meet it and combat it in its strongest and most coherent form. The Church will not shrink from these attacks. She will rather court them. Only see me, she says, what I really am, and then strike me as forcibly as you will or can.

Me, me-adsum qui feci-in me convertite ferrum.

The one thing that is needed now, in appreciating such questions as these, is not a criticism that shall be less severe than at present, but far more so; that it shall analyse to the very bottom not only one religion, but all religions, and not only all religions, but all morality,

that it shall not only discover difficulties, but discover how far these difficulties extend themselves; and that one party shall not seek to damage another by taxing it with inconsistencies that they both of necessity must have in common. Until this is done, no clear result will be arrived at. The spiritual world is at present a battlefield, on which a variety of parties are all struggling for supremacy. But for the most part they cannot see each other's faces, because of the dust of the encounter; and they fight idly like one that beats the air. There is a perpetual struggle only, but there is no victorynothing, despite the intellectual light that is supposed to be prevailing, nothing but

Confused alarms of struggle and fight,
Where ignorant armies clash by night.

W. H MALLOCK

SOME DIFFICULTIES IN ZOOLOGICAL

DISTRIBUTION.

IN offering to the readers of the Nineteenth Century some remarks upon the geographical distribution of animals, I will ask them to excuse me if, in the first place, I shall go rather more into the elementary part of the subject than is perhaps usual in this Review. But distribution' is a comparatively recent branch of biological science; its value and importance are scarcely understood except amongst the most advanced and philosophic naturalists; and unless I am permitted to explain rather fully what distribution' is, I fear I shall not be able to make my readers comprehend the "difficulties' which I wish to notice. I shall, therefore, endeavour first to point out shortly the observed facts of zoological distribution, next to state the hypothesis that will best account for these facts, and lastly to give examples of some of the difficulties that have to be overcome or explained before we can affirm that this hypothesis is perfectly established, and ought to be universally accepted by reasonable persons.

Every animal, such, for example, as a bird, has a certain structure, form, size, and colour, which enable naturalists to assign it to its place in the system amongst its fellows, and to decide that it belongs to a particular family, genus, and species. These attributes of structure, size, shape, and colour are what are called its specific characters,' and are common to all the individuals of the 'species' that the bird in question belongs to. But, besides these more obvious attributes, the species has two other important qualities which are not so generally recognised; that is to say, it exists in a state of nature only within a certain definite area of space, and only through a certain definite lapse of time. Of the latter kind of distribution--that is, of ⚫ distribution in time-I will say nothing on the present occasion, as I wish to confine my remarks to distribution in space, and to recent animals-that is, to such as are now existing on the world's surface.

Well, then, every species, such as that of which this bird is an example, is found in its natural state of existence only within a certain definite area of the world's surface. This area is termed its 'specific

area,' and may be small or large. The little blue magpie of Spain, to which I shall again call attention presently, being found only in certain provinces of Spain and Portugal, is a good instance of limited distribution. Other instances of limited distribution are furnished by certain humming-birds, such as Oreotrochilus chimborazo and O. pichincha, which are found only on the two mountains after which they are respectively named. But in many instances species have a much wider distribution, and in some few cases the area which they occupy is very large, and nearly coextensive with the world's surface. The Barn-owl (Strix flammea), the Osprey (Pandion haliaëtus), and the Turnstone (Strepsilas interpres), are good examples of cosmopolitan species of birds, their specific area being nearly coextensive with the land-surface of the world.

When we proceed to genera-i.e. to groups of species that possess certain characters in common-a similar phenomenon as regards distribution is found to prevail. As in the case of species, genera are mostly confined within a certain definite area, large or small, cases of cosmopolitan or universally distributed genera being quite the exception. For instance, the generic area occupied by the robins (Erithacus) extends over Europe, Africa north of the Atlas, and Northern Asia. Within this generic area three species of robin are met with-namely, our familiar E. rubecula, E. hyrcanus of Persia, and E. akahige of North-east Asia. On the other hand, another of our most familiar birds, the swallow, belongs to a very widely distributed or nearly cosmopolitan genus, species of swallows being met with in every part of the world's surface. In the like manner families, i.e. groups of genera resembling one another in certain particulars, orders, i.e. similar groups of families, and in some cases even higher groups, are more or less limited in the geographical area which they occupy, although, when we come to these larger divisions, it may be naturally supposed that instances of very limited range are the exception. It thus follows that every different part of the world has species, genera, families, and in some cases even orders, peculiar to it, so that a mere glance at a collection of animals from any particular locality will enable the experienced naturalist to tell, often within a very few miles, where the collection has been made.

A second phenomenon attached to specific and generic areas, besides their being limited in extent, is that they are continuous.' We do not find that a species, genus, or other higher natural group, occurs in two separate localities, without being found also in the intervening space. Still less do we find the intervening space occupied by another species of the same group. Take for example the birds of two such countries as England and Japan, which are well known to have a considerable number of species (perhaps one hundred) in common. We expect to find, and do find, that these species are also met with (that is, in such spots as are suitable to their particular

mode of life) all through Northern Europe and Northern Asia. If, therefore, we meet with a species or genus in two distant localities, we may be pretty sure that it likewise exists in the intermediate space.

It is not necessary on the present occasion to pursue this particular branch of the subject further, but we may sum up the results arrived at in the following propositions :

Every species occupies a definite area on the world's surface; and in like manner every genus and family, or other higher assemblage of species, occupies a definite area on the earth's surface; or, more shortly, locality—that is, existence in a certain spot-is quite as much an attribute of any natural group of animals as structure or the possession of a certain form or shape.

Let us now consider a little more closely the mode in which species are distributed within their generic areas. From what has been already stated, it will be evident that a generic area is formed by the sum of the specific areas of the species which belong to the genus. In an ideal generic area the species would be arranged to occupy contiguous areas, and the whole of these contiguous areas would together constitute the 'generic area. Such instances of neatly defined specific and generic areas do not often occur in nature, but still they are to be found in some instances. One of the best examples of them known to me in the class of birds is afforded by the American Bell-birds of the genus Chasmorhynchus. Four species only of this form are known to exist, which, in the male sex at least, are very well marked and easily distinguished. One of these inhabits the forests of Costa Rica and Veragua (C. tricarunculatus), a second (C. variegatus) those of Venezuela, a third (C. niveus) those of Cayenne, and a fourth (C. nudicollis) those of South-east Brazil. The generic area of the genus Chasmorhynchus of course embraces the whole district within these limits. But in most instances, it must be allowed, generic areas are not allotted out in this tidy way. Species frequently overlap each other's areas, and occur three or four in the same district, are absent where they ought to be found, and turn up in localities where they are least to be expected. The arrangement I have here indicated can only be looked upon as an ideal, which, as a careful study of the distribution of animal life shows us, we must always expect to find only approximated to, and more or less concealed by casual irregularities.

I must now say a few words upon another phenomenon of distribution that is, upon what are commonly termed representative' species, as the observed facts connected with them have a very important bearing on the subject. In groups of islands, such as the West India Islands, the Philippines, and the various groups of South

1 Cf. 'The Bell-birds of America.' Intellectual Observer, vol. x. p. 40, 1867.