which Linnæus distributes into two only, Aristotle must be considered as having proceeded upon the more philosophical principle; because the species of these animals, taken collectively, are much more numerous, and much more diversified in their form and structure, than the species of vertebrated animals.

Lamarck's objection to Aristotle's arrangement, on the ground of its commencing with animals of a more complicated instead of those of a more simple structure, is, for more than one reason, of little weight for, in asserting that such an arrangement is contrary to the order of nature, he makes a peculiar hypothesis of his own the basis of that assertion; and, with the exception of Lamarck himself, almost if not all modern naturalists, including Cuvier, adopt the same principle of arrangement as that of Aristotle.

Lamarck objects with more justice to the terms Grape and avaa, as also to the supposed improvement of some modern naturalists by the substitution of the equivalent terms, red-blooded, and white-blooded; because in the second of those two divisions some species are included, as worms, &c. which have red blood. On this ground Lamarck proposed to divide all animals into those which have, and those which have not, vertebra; or into vertebral and invertebral animals.* And he extended the two invertebral classes of Linnæus to five, and subsequently to ten.t

With reference to the classification of Aristotle, as expressed in his first book, it has been occasionally observed by literary men, who were not familiar with the details of his history, that quadrupeds in general and reptiles are excluded. "The most comprehensive groups into which the greater number of animals may be distributed," he says, "are these: one, of birds; one, of fish; one, of whales and other cetaceous animals; all of which have blood.

*Philos. Zool. tom. i. p. 116, &c. +Ibid. p. 121, 122.

There is another group of the ὀστρακοδέρμα; another, of the μαλακόστρακα; another, of the μαλάκια; and another, of the ἔντομα; all of which are without blood. Of those animals which do not come within the foregoing arrangement, there are no comprehensive groups; for no individual type comprehends many species: and there is one type which is unique, affording only a single species, namely, man. Some types afford different species without a difference of specific denomination: thus there are red-blooded quadrupeds, of which some are viviparous, and others oviparous."

(Γένη δὲ μέγιστα τῶν ζῴων, εἰς ἃ διήρηται τἆλλα ζώα, τάδ ̓ ἐστὶν, ἓν μὲν ὀρνίθων, ἓν δ ̓ ἰχθύων, ἄλλο δὲ κήτους. Ταῦτα μὲν οὖν πάντα ἔναιμά ἐστιν. ἄλλο δὲ γένς ἐστὶ τὸ τῶν ὀστρακοδέρμων —ἄλλο τὸ τῶν μαλακοστράκων-άλλο τὸ τῶν μαλακίωνἕτερον τὸ τῶν ἐντόμων. Ταῦτα δὲ πάντα μέν ἐστιν ἄναιμα—Τῶν δὲ λοιπῶν ζῴων οὐκέτι τὰ γίνη μεγάλα· οὐ γὰρ περιέχει πολλὰ εἴδη ἓν εἶδος, ἀλλὰ τὸ μέν ἐστιν ἁπλοῦν αὐτὸ οὐκ ἔχον διαφορὰν τὸ εἶδος, οἷον ἄνθρωπος, τὰ δ ̓ ἔχει μὲν, ἀλλ' ἀνώνυμα τὰ εἴδη. Εστι γὰρ τὰ τετράποδα καὶ μὴ πτερωτὰ ἔναιμα μὲν πάντα, ἀλλὰ τὰ μὲν ζωοτόκα τὰ δ ̓ ᾠοτόκα αὐτῶν. Ρ. 10.)

"And though there are many species of viviparous quadrupeds, yet they have no collective denomination; but each is distinguished, as in the case of the human species, by its proper name; as the lion, deer, horse, &c. on which account we cannot describe them collectively, but must consider the individual nature and character of each."

(Τοῦ δὲ γένους τοῦ τῶν τετραπόδων ζῴων καὶ ζωοτόκων εἴδη μέν ἐστι πολλὰ, ἀνώνυμα δέ· ἀλλὰ καθ ̓ ἕκαστον αὐτῶν ὡς εἰπεῖν, ὡσἄνθρωπος εἴρηται, λέων, ἔλαφος, ἵππος-Διὸ καὶ χωρὶς λαμ βάνοντας ἀνάγκη θεωρεῖν ἑκάστου τὴν φύσιν αὐτῶν. Ρ. 10.)

περ

It is interesting to observe that even Cuvier occasionally experiences a similar difficulty in his classification; and expresses himself, with reference to the difficulty, in nearly the same terms as Aristotle. Thus, in introducing his third order of the mammalia, called carnivora, he says, "The forms of the different genera of this order are so various, that it is impossible to range them in the same series: they are

therefore divided into several families."* And of one of these families, the marsupialia, to which the opossum and kanguroo belong, he observes, that "the the genera of that family might form a distinct order, so very peculiar is their structure."† And on another occasion he adds, with respect to this same family, that "although the various species so closely resemble each other in many points as for a long time to have been classed in one genus only; they yet differ so widely in their feet, and teeth, and organs of digestion, that, considered with reference to those parts, they might be distributed, not into one but several orders;-and might constitute even a separate and parallel class of mammalia.”§

In addition to the natural groups, enumerated in the distribution above described, Aristotle. refers to a few marine animals which principally belong to the zoophytes of Cuvier, without comprehending them under a distinct name. Of that extensive class of animals, called at the present day polypes, which are the fabricators and inhabitants of every variety of coral, he says nothing: and of that still more extensive class, if the term class be not too confined, the animalia infusoria, he was almost necessarily ignorant; most of the species being microscopic.

*"Les Carnassiers.-Leurs formes et les détails de leur organisation varient beaucoup-au point qu'il est impossible de ranger leurs genres sur une même ligne, et que l'on est obligé d'en former plusieurs familles qui se lient diversement entre elles par des rapports multipliés." Tom. i. p. 121.

"Les Marsupiaux-pourraient presque former un ordre à part, tant ils offrent de singularités dans leur économie." Tom. 1. p. 169.

"Malgré une ressemblance générale de leurs espèces entre elles, tellement frappante, que l'on n'en a fait long-temps qu'un seul genre, elles diffèrent si fort par les dents, par les organes de la digestion et par les pieds, que si l'on s'en tenait rigoureusement à ces caractères, il faudrait les répartir entre divers ordres." P. 170.

§ “On dirait, en un mot, que les marsupiaux forment une classe distincte, parallèle à celle des quadrupèdes ordinaires."

P. 171.

It appears, from a few scattered notices, that Aristotle had a faint idea that the specific characters and dispositions of animals might be altered, from the effect of food and other circumstances: (τῶν ζῴων τῶν τετραπόδων πολλὴν αἱ χῶραι ποιοῦσι διαφορὰν οὐ μόνον πρὸς τὴν ἄλλην τοῦ σώματος εὐημερίαν ἀλλὰ καὶ πρὸς τὸ πλεονάκις ὀχεύεσ θαι καὶ γεννᾶν. Ρ. 122. Ὅσα μὲν οὖν μαλακὰς ἔχει τὰς τρίχας, εὐβοσία χρώμενα σκληροτέρας ἴσχει, ὅσα δὲ σκληρὰς μαλακωτέρας καὶ ἐλάττους. Διαφέρουσι δὲ καὶ κατὰ τοὺς τόπους τοὺς θερμο τέρους καὶ ψυχροτέρους. Ρ. 68. Ενίοτε γίνεται τῶν μονοχρέων ἐκ μελάνων τε καὶ μελαντέρων λευκὰ ἐκ δὲ τῶν λευκῶν γενῶν οὐκ ὦπται εἰς μέλαν μεταβάλλον. Ρ. 71.) And he mentions particularly one instance of this kind, though his reasoning on the occasion is not admissible in the present state of physiological knowledge. In observing that, "as the actions of animals are determined by their natural affections and physical powers, so their moral habits, and even some of their physical characters, are capable of being altered by their actions;” he says, that “the common hen, if she have fought with and vanquished the cock, will begin to crow, and to imitate the cock in various ways; and her comb will increase, and her plumage alter to such a degree as to make it difficult to determine whether she be really a hen: even spurs, though small, will sometimes grow on her legs.'

(Ὥσπερ δὲ τὰς πράξεις κατὰ τὰ πάθη συμβαίνει ποιεῖσθαι πᾶσι τοῖς ζῴοις, οὕτω πάλιν καὶ τὰ ἤθη μεταβάλλουσι κατὰ τὰς πράξεις, πολλάκις δὲ καὶ τῶν μορίων ἔνια, οἷον ἐπὶ τῶν ὀρνίθων συμβαίνει. Αἵ τε γὰρ ἀλεκτορίδες ὅταν νικήσωσι τοὺς ἄρρενας, κοκκύζουσί τε μιμούμεναι τοὺς ἄρρενας καὶ ὀχεύειν ἐπιχειροῦσι, καὶ τό τε κάλλαιον ἐξαίρεται αὐταῖς καὶ τὸ οὐροπύγιον, ὥστε μὴ ῥᾳδίως ἂν ἐπιγνῶναι ὅτι θήλειαί εἰσιν· ἐνίαις δὲ καὶ πληκτρά τινα μικρὰ ἐπανέστη. Ρ. 302.)

The fact is nearly as Aristotle states it; and, to a certain extent, similar facts are observable in the human species as well as in other animals; namely, that the peculiar characters of the female are occasionally obscured, with respect both to the physical form and the moral habits. But, in reasoning on the

X

phenomena, Aristotle mistakes the effect for the cause. The circumstance of having fought with the cock is not the determining cause of the change in the external form of the hen: but the alteration itself in the external form is dependent on, or at least coincident with an imperfect developement, or a subsequent alteration, of the internal structure; which imperfect developement or subsequent alteration determines that degree of masculine courage which prompts the hen to fight, and to imitate the male in other actions.

And so it sometimes happens that, in females of the human species, the feminine form is either never originally developed, or, by age or other causes, becomes so much altered as to lose its usual characters; (γυνὴ δὲ τὰς ἐπὶ τῷ γενείῳ οὐ φύει τρίχας· πλὴν ἡνίαις γίγνονται ὀλίγαι, ὅταν τὰ καταμήνια στῇ. P. 70.) And, correspondently with these exterior traces of virility, there is often in such cases a masculine temperament of the mind, which marks the character of the virago. And, on the other hand, from analogous causes analogous changes are found to take place in the male of our own species, or of any species nearly resembling our own: for, in such instances, the tone of the voice and the general form of the body acquire a feminine character; and that firmness and resolution, which belong naturally to the male, subside to a greater or less degree into a feminine gentleness.

Aristotle, then, had no philosophical notion of the laws which regulate the occasional variation in the specific form of animals; much less of the limits of that variation: for the accurate developement of which, the scientific world, and more than the scientific world, are deeply indebted to the skilful researches and correct reasonings of Cuvier; whose fame will rest securely on this natural and imperishable basis, when his own and all other artificial systems of classification, for artificial we can see them to be even in the present state of our knowledge, will probably have been overturned by the