30 
FIRST CLASS OF THE VERTEBRATED ANIMALS. 
tongue is originally small as we find iu the Fishes. The nose and car present no 
external projection, in which respect they again resemble these organs in the Cetacea, 
and in the great oviparous animals. Again, the eye appears at first without an eye- 
lid, as it is always found in Insects, the Crustacea, the Mollusca, the Fishes, and 
certain Reptiles. 
Finally, the general form of the human embryo does not exhibit a less degree of 
analogy with the perfect states of other animals. Tho head is at first so slightly de- 
veloped, as to give to the body of the embryo the appear.inco of an Invertebrated 
Auirnal. It resembles a Fish or a Reptile by tho absence of limbs; and the caudal 
or tail-like appendage, which we have already mentioned, gives it for a short time tho 
aspect of an ordinary quadruped. 
From what has been said, it appears that the embryos of the higher animals exhibit 
in the course of their growth the greater part of the characteristic peculiarities of 
all classes of animals, and present the fleeting models of almost all the different kinds 
of organization. The rudiments of Man thus form a reduced, yet striking, image of 
the entire Animal Kingdom. 
We must admit, however, that these rescmblancps which have Just been enume- 
rated arc far from establishing among all beings a perfect and absolute identity, 
whether we consider different animals in their states of perfection, or upon comparing 
one animal at the different ages of its progress, and with other animals of different yet 
inferior species. Every animal preserves continually, and throughout every ^e, certain 
well-marked characters peculiar to its species. These dUferences are so striking, 
even iu those which appear to resemble each other most nearly, that it becomes 
impossible for us to conclude, that they may all be arranged in one graduated scale, 
every where complete and continuous; or that they all possess one common frame- 
work, one visible and identical basis, with the same number of essential organs, pos- 
sessing the same natural characters. Still less can they be supposed to be derived 
by gradual metamorphoses and complications from one common stock, from binary, or 
even from ternary types. These analogies being always partial, and frequently vague, 
can by no means warrant the adoption either of the universal chain of existence pro- 
posed by Bonnet, or tho transmutation of species, and the successive filiation of 
Demaillet and Lamarck. Still less will they admit the adoption of the organic 
identity proposed by certain French and German writers. 
If animals resemble each other universally, it is only in the great phenomena of 
existence, of which we have already treated. When, however, wc descend to the 
instruments producing these phenomena, we are surprised to find tho most striking 
difference, instead of resemblance, which can be considered as perfect. One animal 
seemingly superior to another in some of its organs, is often evidently inferior to 
the same animal in other details of its structure. Wc sometimes find that two animals 
which resemble each other entirely in respect to one set of organs, are sometimes so 
dissimilar in their conformation, that it is impossible to blend them together even in 
imaginatvon. Finally, there are some organs of which certain entire classes of ani- 
mals arc altogether deprived, and yet they may exhibit, in two other classes of animals 
apparently allied to each other, the most discordant characters. Indeed, it is cer- 
tain that there is not a single organ which does not vary from one genus or from 
one family to another ; but at tbe same lime, there is net an organ, except perhaps 
the stomach, which can be found in all families and in all genera. We shall see 
numerous proofs of this in the details of the Animal Kingdom. 
Tho real cause of analogies among different ages and species must be found in this, — 
that they are all constructed upon models evidently ayialoyous. The same Divine 
Artificer formed them all. We find the same style in every page of the great book 
of Nature ; and we every where see the most evident affinities both in the essential 
organs of animals, and in the phenomena which they exhibit. 
From what has already been said, we may easily perceive the cause of those wonder- 
ful productions, those Lusus NatureCy or monstrous births, which in all ages have 
astonished and alarmed the ignorant. These evidently arise from a retardation in the 
growth of some organs. An animal, though remaining incomplete in regard to one 
organ, may yet continue to grow in all other respects, and the disproportion of tho 
organs may thus proceed to the most shocking disparity. Another consequence of 
this law is, that the abortive and imperfect organs of an animal must resemble the 
usual organs of the same animal in an earlier state of its existence, or those of a lower 
animal in an adult form. Though all the organs may have been originally perfect, 
yet if one ceases to develop itself, while all the others continue their progress, the 
monstrosity of the final result is the necessary consequence. 
It follows also, that what is a deformity in one animal, may he a constant and per- 
manent character of another. The monstrosity of a higher animal may bear a decided 
analogy to the regular form of one of another grade. For example, it is evident that 
one of the Mammalia, bom without hair, is analogous to tho lowest classes of ani- 
mals having the skin naked. If the skin be scaly, it brings tho Quadrupeds down to 
the level of the Fishes and the Ophidian Reptiles. The Mammalia and Man often 
have a divided palate, like the Birds, the FLshos, and many Reptiles. Tho occasional 
absence of the teeth in Mammalia may be explained on the same principle. The mon- 
strous development of the liver is found naturally in Birds, Fishes, and also in some 
Cetacea and Reptiles. To want the tongue, or to have it forked — to have the limbs 
abortive, or altogether wanting, though monstrous developments, are natural and 
constant arrangements in other species. 
The following are the most remarkable of tho laws of Monstrosity, or, as Lord Bacon 
calls them, “ tho laws which govern tho sports of Nature:"— 
1. Monstrosities are always found more frequently in females than in males. The 
cause of this is to be found in the fact, that the male sex is a more advanced state 
of development than the female. All embryos, of whatever sex they may ulti- 
mately be, arc at one time females. In infancy, too, the female character predomi- 
nates. Young boys preserve for many years the smooth chin, the narrow larynx, the 
silver voice, and tho rounded limbs of the young female. The young birds of both 
sexes have at first the same plumage as their mothers, and moult at the same time 
that they do. Tho same thing holds with all the other characteristics of the male 
sex. The mane of the Lion, the crests, spurs, and other omamouts of tho male 
Birds, the antlers of Stags, the horns of Cattle, the vivid colours and powerful energy 
which belong to the males of different species, are all characters slow in developing 
themselves. 
2. Monstrosities never exceed certain limits, and deformities have their fixed laws. 
Thus, when there are supernumerary fingers, they are always similarly disposed. 
3. They always preserve a degree of symmetry, even among the most shocking 
irregulariti<*s. A double monster seems to result from the same law, which occasions 
both sides of the body to be symmetrical. 
4. The absence or excessive smallness of one organ is always followed by the ex- 
treme development of another. 
5. Monstrosities arc more frequently found in tho left side than in tho right, be- 
cause the left side is always tlie more feeble and imperfect. 
6. Deformities generally go together in pairs. Thus, the presence of suporrmme- 
rary fingers and the division of the palate ; the excessive smallness of the lungs, with 
a great development of tlio liver; and these dispositions, which usually co*cxist in 
monsters, are found naturally in many animals. 
7. The most diversified organs of the animal series are the most liable to monstro- 
sity in the higher animals. 
8. Monsters always have some of their organs below their age, and consequently 
below their class, but never above them. A monstrous Bird or Quadruped often has 
Its organs analogous to those of a Reptile or of a Fish; but a Fish or Reptile never 
has those of a Bird. This rule is general and constant. 
Several more laws might be mentioned, but these seem sufficient for our present 
purpose. We shall now proceed to consider the Animal Kingdom more in detail, and 
accordingly commence with the Mammalia. 
THE FIRST CLASS OF THE VERTEBRATED ANIMALS. 
THE MAMMALIA— MAN AND BEASTS. 
WITH WAEM blood; HEART WITH TWO VENTRICLES; FEMALES "SUCKLING TIIEIR YOUNG WITH MILK SECRETED IN BREASTS OR MAMM.E; VIVIFAROUS 
EXCEPTING THE MONOTREMATA, WHICH ARE EITHER OVIPAROUS OR OVO-VIVIPAUOUS. 
The Mammalia should be placed at the head of the Animal Kingdom, 
not only because it is the class to which Man himself belongs, but be- 
cause it surpasses all others in the enjoyment of more numerous facul- 
ties, of more delicate sensations, of a greater variety of motions, and 
where all these properties are combined so as to form lieings of greater 
intelligence, fruitful in resources, less the slaves of instinct, and more sus- 
ceptible of improvement- 
This class possesses characteristics peculiar to itself, in its viviparous 
generation [the young being born alive], in the manner by which the 
foetus [or embryo] is noiirisiied in the womb, by means of the placenta, 
and in the mamm^, or breasts, by which the young are suckled. 
On the contrary, the other classes are oviparous [or produced from eggs 
previously laid by the parent] ; and if we contrast them generally with 
the Mammalia, we shall find that they possess numerous points of resem- 
blance among themselves, which clearly exhibit a special plan of organiza- 
tion in the general system of the Vertobrated animals. 
As the degi-ee of their respiration is moderate, tlie Mammalia are in 
general adapted for walking upon the ground, but at the same time tlieir 
movements are performed with vigour, and in a continuous manner. 
For this reason, the articulations of their skeletons have very precise 
forms, which determine the direction and extent of their motions with 
precision. 
Some of them can, however, raise themselves in the air by means of 
elongated limlis, connected by extensible membranes ; otliors have their 
limbs so much shortened that they cannot move easily except in the 
water. But this circumstance by no means deprives these last-men 
tioned animals of the general characters of the class. 
ThU variety in the character of their locomotion requires a corresponding diflef 
