58 



FIRST CLASS OF THE VERTEBRATED ANIMALS. 



It is evident that we can only ascertain the effect which a very long time will pro- 

 duce, by comparing it with the change actually observed to have taken place during 

 a shorter period. MM. Cuvier and Geoffroy-Saint-Hilaire sought out the most 

 ancient documents which Egypt could afford, for the purpose of solving this question, 

 so important to the Naturalist, and essential to a knowledge of the past history of our 

 globe. M. Cuvier examined with great care the ancient Egyptian obehsks trans- 

 ported to Rome, and found a perfect resemblance between the general form of the 

 animals engraved thereon, and the common species of our own day. M. Geoffroy 

 collected as many mummies of the lower animals and of ftlan as he could find, and 

 was led to form a similar conclusion. These monuments must have been from 2000 

 to 3000 years old. " For a long time," says M. Lacepede in the report which he 

 made upon these objects in common with MM. Cuvier and Lamarck, — -*' For a long 

 time philosophers have been anxious to know whether species change their forms dur- 

 ing the course of ages. This question, apparently trivial, is yet essential to the history 

 of the globe, and to the solution of a thousand other questions not far removed from 

 the gravest objects of human veneration. Never were we in a better condition to 

 decide the question upon a great number of remarkable species, and for a long period 

 of years. The superstition of the ancient Egyptians would almost seem to have 

 been inspired by Nature, for the purpose of bequeathing to us a monument of her 

 history. A people of fantastical opinions, by embalming with so much care the 

 brute beings, objects of their stupid adoration, have left in their sacred grottoes com- 

 plete cabinets of zoology. The climate has united with the art of embalming to 

 preserve these bodies from all corruption, and we have now the means of ascertaining 

 with our own eyes what was the condition of these animals 3000 years ago. One 

 can scarcely restrain the raptures of Imagination upon seeing at the present day an 

 animal preserved, with the smallest bone and hair perfectly distinguishable, which 

 had 3000 years since in Thebes or Memphis its priests and altars. But without 

 wandering into all the subjects to which these associations give rise, we shall confine 

 ourselves to noticing the simple fact — that these animals perfectly resemble those of 

 the present day." 



Although the bones of a species do not vary to any extent, yet the identity of 

 osteological characters is not alone sufficient to establish an identity of species ; and 

 some species w*hich possess a most exact similarity of structure are held, by the ge- 

 neral consent of Naturalists, to be of different species. It is almost impossible to dis- 

 tinguish the skeleton of the "Wolf from that of the Wild Dog of New Holland. Their 

 teeth are the same ; the vertebrae of the tail are equal in number ; the feet have the 

 same number of toes ; and the bones of the head exhibit the same relations, except 

 that the orbital fossae are slightly larger in the Wolf. The same thing occurs in the 

 Wolf of Canada, which is smaller than the common Wolf, and larger than the Dog 

 of New Holland. The Jackal also resembles the Wolf- Dog very closely, especially 

 in the form of the head. There is likewise a most exact similarity in respect to the 

 organs of Sense among the New Holland Dog, the Canadian Wolf, and the Jackal. 

 Again, the quality and arrangement of the hair exhibit no essential differences, for they 

 all may have either woolly or silky hair, according as they have been naturalized in cold 

 or temperate countries. In fact, they only differ in colour. Yet all these genera 

 merely vary from white to brown or black, and excepting the Black Wolf, which has 

 the hair of a uniform colour, the others have hairs of fawn, black, or white so mingled 

 together, that it is difficult to set down any colour as peculiar to either species, and 

 which will not pass by insensible shades into another. 



What, then, it may naturally be inquired, forms the distinction between a species 

 and a mere variety ; and how are we to ascertain those permanent characters which 

 were assigned to our domestic animals at the origin of things ? 



If these questions be considered in a purely abstract form, no difficulty can arise, as 

 we have only to include in the same species all those animals, whose differences of 

 external form and garb can be traced to some acknowledged causes of variation ; 

 while the animals whose differences cannot be thus explained, must be held to belong 

 to separate species. " Where two races of animals are distinguished by any undeviating 

 mai'ks in such a way that they never will, under any circumstances, pass into each 

 other, or that the progeny of either can never acquire the characters of the other, they 

 are of distinct species, and it matters not how wide or how nai-row be the hne of dis- 

 crimination, provided that it never be broken in upon." But when we come to apply 

 these abstract rules to the realities of Nature, we find that they are not always suffi- 

 cient to distinguish the mere variety from the genuine species. 



The difficulty is further increased by the circumstance that many varieties or races 

 of some species differ more decidedly among themselves, than the species of certain 

 genera, where the objects are very numerous. Again, the greater part of our acquisi- 

 tions are imported from remote and barbarous countries. *' A large proportion," as 

 ]\'Ir Lyell observes, " have never even been seen alive by scientific inquirers. Instead 

 of having specimens of the young, the adult, and the aged individuals of each sex, 

 and possessing means of investigating the anatomical structure, the peculiar habits 

 and instincts of each, what is usually the state of our information ? A single speci- 

 men, perhaps, of a dried plant, or a stuffed bird or quadruped ; a shell without the 

 soft pai-ts of the animal ; an insect in one stage of its numerous transformations ; — 

 these are the scanty and imperfect data which the Naturalist possesses. Such infor- 

 mation may enable us to separate species which stand at a considerable distance from 

 each other ; but we have no right to expect any thing but difficulty and ambiguity, 

 if we attempt from such imperfect opportunities to obtain distinctive marks for 

 defining the chai'acters of species which are closely related. When our data are so 

 defective, the most acute Naturalist must expect to be sometimes at fault, and, hke 

 a novice, to overlook essential points of difference, or pass unconsciously from one 

 species to another." 



Buffon established the criterion for the determination of species in the power of 

 producing, by their union, races equally fertile with themselves, and this rule seemed 

 to be confirmed by the experiments of John Hunter. They were of opinion, that 

 *' if a male and female produce an offspring which is prolific, the tribes to which the 

 parents respectively belong are hence proved not to be specifically different, and 

 whatever diversities may happen to characterize them, are in this case to be looked 

 upon as examples of variation. But if the third animal be unprolific, it is to be con- 



cluded that the races from which it is descended are originally separate, or of distinct 

 kinds. The fact that most hybrid animals are wholly xmprolific, would appear to be 

 a provision for the attainment of this desirable end, and for maintaining the order 

 and variety of Nature. For if such had not been the condition of these intermediate 

 animals, we have reason to believe that all the primitive distinctions would have been 

 long ago totally effaced ; a universal confusion of species must have ensued, and there 

 would not be at this day one pure and unmixed species left in existence. The Na- 

 turahsts above mentioned, inferring, from the apparent utility of this law, that it must 

 universally prevail, obtain by means of it a ready method of determining on identity 

 and diversity of species." 



It is very clear that if two animals are prevented by any great disparity of organi- 

 zation or disposition from uniting, that the criterion of generation holds good to a 

 certain extent. The Bull and the Goat, for example, would at once be pronounced to 

 be distinct species. This rule may enable us to assert that two animals are not of the 

 same species, but it does not always serve to discriminate between nearly-alUed species. 

 Hence it seems rather to be the first rude attempt at forming a criterion, than one 

 which serves to mark out nice distinctions. The crosses among the Dog, the Wolf, 



and the Jackal; — between the Goat and the Sheep;— the Horse and the Ass; 



the Lion and the Tiger, with the occasional appearance of fertile Hybrids in many, 

 and the possibiHty of its occurrence in them all, show that the converse often fails. 

 Although animals which do not generate together belong to distinct species, yet it is 

 not true that distinct species must not generate together, nor does it follow that their 

 progeny must always be sterile. 



The determination of species by the property of producing fertile races, had previously 

 been restricted by Frisch to such as generate together of their own accord, *'von Natur 

 mit einander gatten." Those artificial unions brought about by restraint, artifice, or 

 domestication, were wholly excluded by him. But this restriction renders the rule 

 useless in practice for determining those points where difficulties may chiefly be ex- 

 pected to arise. It is in respect to Man and the domestic animals, or with animals 

 brought from distant and uncivilized countries, that a rule is most required to distin- 

 guish the species from the mere variety. Blumenbach inquires, " When will it come 

 to pass that all nearly-allied animals shall be brought together from remote countries, 

 so as to submit them to the requisite experiments, — for example, whether the Chim- 

 panse (Troglodytes niger) from the Angola Coast, will form a fertile race with the 

 Orang Outang (Pithecvs Satyrus) from Borneo?" This is a desideratum which the 

 general establishment of Zoological Gardens alone can supply, but in the meantime 

 we must seek some other criterion, which shall be appHcable to Man and the domes- 

 ticated animals, for the determination of species. 



It is here that difficulties arise in drawing the Hne between the species and the 

 variety. Tillesius considers that several distinct species are confounded under the 

 name of Jackal or Chacal (Canis aureus), while both Pallas and Guldenstaedt re- 

 garded the Jackal of Caucasus as the original source whence our domestic Do^s are 

 descended. Others again thought that the different kinds of Dog have diverged from 

 the Shepherd's Dog, while some considered them all but as degenerations from the 

 Hysena, the Wolf, or the Fox. 



Thus it is precisely in those places where a fixed rule is most required that the 

 breeding principle wholly fails, and we may seek in vain for any other. Blumen- 

 bach could propose none, but referred the determination of species to Analogy and 

 Probability. " Fere desperem," he observes, " posse ahunde quam ex Analogia 

 et verisimilitudine notionem speciei in Zoologiae studio depromi." (I may almost de- 

 spair of being able to derive the idea of species in the study of Zoology from any other 

 source than analogy and probabihty). Two races of animals which possess a general 

 resemblance, and differ only in those respects which have been observed to vary, and 

 can be traced to some well-known causes of variation, must at once be admitted to 

 belong to the same species ; but however near their general appearance may be, if 

 they exhibit any difference which, in all our experience of the Animal Kingdom, has 

 never been known to exist as a variety, they must be set down as distinct species. 

 The proper determination of species rests, therefore, upon the knowledge of an im- 

 mense number of facts, and forms one of the most difficult, as it is one of the most 

 important, subjects to which the NaturaHst can direct his attention. 



Thus Blumenbach considers the Ferret to be merely a variety of the Pole-Cat 

 ■ (Mustelaputorius), not because they generate together, for perhaps the experiment- 

 may not yet have been made, but because the former is white with red eyes ; and, 

 from that well-known rule of analogy, that the same effects must be referred to the 

 same causes, its origin is the same with those Albino varieties' produced daily among 

 the domesticated Mammalia. Again, the Indian Elephant (Elephas Indicus) differs 

 remarkably from that of Africa {E. Africanus) in the number and form of its molar 

 teeth. Whether these animals will engender together it is perhaps difficult to deter- 

 mine; but on examining every specimen which reaches this country, the same differ- 

 ence is found to exist. Further, we know of no analogous instance of variety in the 

 formation of the molar teeth among wild or domestic animals. We, therefore, do 

 not hesitate to set down these two Elephants as distinct species. 



There are other difficulties arising from the want of accurate information; and these, 

 in the present state of the science, occur but too frequently. For example, the skin 

 of an animal arrives from the Cape of Good Hope. At the first glance it appears, 

 perhaps, to be a specimen of the common Cape Otter (Lutra capensis), and this 

 opinion may be fm-ther confirmed on examining the structure of its teeth. The colour 

 of the breast and throat may seem of a purer white, and to be more extensive than 

 usual, but this is a characteristic which might belong to a mere variety. On looking 

 - at the feet, we arc much surprised at finding all the toes without nails, exceptmg 

 on the second and third of the hinder-feet, where only a rude vestio-e of a nail 

 can be observed. A Carnassier without claws would seem an anomaly in creation. 

 To suppose a being, compelled by its structure to live on animal food, and yet to be 

 refused by Nature the weapons fitted for seizing its prey, disturbs our ideas of final 

 causes, and we delight to trace order and regularity in the works of creation. The 



specimen must then be imperfect. It belongs to an old individual; perhaps the 



claws may have dropped off through age or disease. We set it down, therefore, 

 as a mere variety of the Lutra caperisis. Some years afterwards, youn" indi- 



