MR VICE-CHANCELLOR AND GENTLEMEN OF THE

UNIVERSITY,

My first impulse in availing myself of the privilege of addressing you in this place, is, to give expression to the deep sense which I entertain of the honour conferred on me by my appointment to 'Sir Robert Reade's Lectureship,' especially as it is the first which has been made since the revival of that ancient foundation. Believe me, Sir, I truly appreciate the favour of your choice, and am fully impressed with the responsibilities which it involves. And if my acknowledgments should seem curt or inadequate, I would beseech you to believe that this results from the wish not to trespass too long on your most valuable time, but to devote to the subject selected as much as may be of the period commonly allotted to an oral discourse.

In reviewing, for the choice of this subject, the field of Natural Science in which I am a labourer, I desired to select one that might be treated of with a certain degree of completeness in a single Lecture, one that would enable me to submit to you some of the more recent generalisations in Natural History, and at the same time exemplify the applicability of that science, as a discipline, to the improvement of the intellect, and especially as a sharpener of the faculties of observation and of methodical arrangement.

I trust that in the attempt to briefly unfold the Classification and Geographical Distribution of the Mammalia I may attain the end I have in view.

The generalisation resulting in the idea of the natural group of animals, so called, is one of ancient date. The ZOOTOKA of Aristotle included the same outwardly diverse but organically similar beings which constitute the MAMMALIA of modern Naturalists. In that truly extraordinary compendium of zoological and zootomical knowledge, the 'Пepì Sawv ioTopías1,' animals generally, and by implication the

1 Ed. Schneider, Leipzig, 1811, 4 Vols. 8vo.

B

Zootoka, or air-breathing vivipara, are divided according to the nature of their limbs into three sections:-1st, Dipoda; 2nd, Tetrapoda; 3rd, Apoda. The first comprised the biped human race, the second the hairy quadrupeds, the third the whale-tribe, in which the limbs answering to the legs of man are wanting.

The second of these divisions, which includes the great majority of mammals, and is commonly regarded as the class itself, Aristotle subdivides into two great groups, according to the modification of the extremities. In the first group the foot is multifid, and a part of the digit-finger or toe—is left free for the exercise of the faculty of touch, the hard nail or claw being placed upon one side only; in the second group the digits are inclosed in hoofs: these groups are recognised in modern Zoology as the UNGUICULATA and UNGULATA.

Aristotle, in the generalised expressions of his observations on the various conditions of the teeth, has indicated subdivisions of the UNGUICULATA according to characters of the dental system. One subdivision includes those quadrupeds which have the front teeth trenchant, and the back teeth flattened, viz. the Pithecoïda or Ape-tribe. Another subdivision includes the quadrupeds with diversified acuminated front teeth and interlocking serrated back teeth, viz. the Karcharodonta, or Carnivora; whilst the animals now known as "Rodents' are indicated by a negative dental character.

With respect to the hoofed or Ungulate quadrupeds Aristotle in his generalisations on the organs of progressive motion divides them into Dischida, or bisulcate quadrupeds, and Aschida, or solidungulates, e. g. the horse and ass.

The term Anepallacta, by which Aristotle signified the animals in which the upper and lower teeth do not interlock, is applicable to the herbivorous quadrupeds generally; in which the Amphodonta, or those with teeth in both jaws, e. g. the horse, are distinguished by him from those in which the front teeth are wanting in the upper jaw, e. g. the ox.

The bats were rightly recognised as true Zootoka, and the genus was defined as Dermaptera.

The apodal Vivipara, which form the third of Aristotle's more comprehensive groups, embraces the Ketode, now called Cetacea, and affords, by its position and co-ordinates in the great philosopher's zoological system, one of the most striking examples of his sagacity and research. In generalising, however, on modes of reproduction Aristotle includes certain sharks with the cetaceans, distinguishing the former by their gills, the latter by their blow-hole.

I ought, also, to remark that, although Aristotle has exemplified groups of animals which agree with many of the modern Classes, Orders, and Genera, their relative value is not so defined1; and his, in most respects, natural, assemblages would have commanded greater attention and been earlier and more generally recognised as the basis of later systems, had its immortal author more technically expressed an ap→ preciation of the law of the subordination of characters; but Aristotle applies to each of his groups the same denomination, viz. yévos, genus; distinguishing, however, in some cases, the greater from the less.

Centuries elapsed ere any advance was made in the science of Zoology as it was bequeathed to the intellectual world by the mind of Aristotle. Of no other branch of human knowledge does the history so strongly exemplify the fearful phenomenon of the arrest of intellectual progress, resulting in the 'dark ages.' The well-lit torch which should have guided to further explorations of the mighty maze of animated nature was suffered to fall from the master-hand, and left to grow dim and smoulder through many generations ere it was resumed, fanned anew into brightness, and a clear view regained both of the extent of ancient discovery and of the right course to be pursued by modern research.

1 See the just and discerning remarks on this subject by Dr WHEWELL, in his admirable History of the Inductive Sciences, 3rd ed., Vol. III. p. 289.

B 2

TO JOHN RAY, an ornament of this University, I would ascribe the merit of proposing a classification of the Zootoka, which first claims attention as in any respect an advance upon that taught by the Father of Natural History. It is given in a tabular form in Ray's Synopsis Methodica Animalium Quadrupedum, and is as follows:-(See p. 5).

of

In this Table the principle of the subordination of characters, or of their different values as applicable to groups different degrees of generalisation, is clearly exemplified; and herein perhaps is its chief value. But, in the exclusion of the Dipoda and Apoda of Aristotle, Ray manifests a less philosophical appreciation of the extent and essential nature of the class Zootoka than his great predecessor. He is also inferior in the discernment of the real significance of certain modifications of zoological characters. Aristotle was not deceived either by the claw-like shape of the hoofs of the camel, or by the degree of subdivision of those of the elephant; he knew that both quadrupeds were, nevertheless, essentially Ungulate1.

LINNEUS first definitely and formally restored the great natural class I am now treating of to its Aristotelian integrity; and, applying to it that happy instinct of discernment of significant outward characters which had enabled him to effect so much for the sister Science of Botany, he proposed for it the name MAMMALIA.

The active cultivation of the science of observation stimulated by Ray, Linnæus and Buffon, had brought to light instances, e. g. in certain lizards, of viviparous quadrupeds which differ in structures of classific importance from the Zootoka tetrapoda of Aristotle. Certain forms of true fishes were now known to bring forth their young alive, as well as the fish-like Ketode. The term Zootoka ceased to be applicable, exclusively, to the class of which Aristotle had sketched out the bounds; and Naturalists gladly accepted and have since retained the neat and appropriate and truly distinctive

1 ‘Καὶ ἀντὶ ὀνύχων χηλὰς ἔχει.