4p 
SPECIES. 
eration of species cannot have existed, and we | themselves with leaping from tree to tree, and 
derive from the known insufficiency of the pre- 
sent causes of change a positive ground for in- 
ferring their descent from distinct original types. 
The mere circumstance of our being able to in- 
duce by art and contrivance a fertile union be- 
tween two species, is not sufficient to counteract 
this evidence, when we see that these same spe- 
cies preserve themselves distinct in the wild 
state, and continually maintain certain weil-de- 
fined peculiarities. Pallas was led to infer that 
some of our domestic animals, such as the sheep, 
the goat, and the dog, are factitious beings, not 
proceeding from any permanent origin, but from 
| the union of several distinct species, such as the 
dog from the wolf, the fox, and jackal; the sheep 
from the mouflon and Siberian argali; and the 
common goat from the Persian and Caucasian 
goats with the ibex. We know that these ani- 
mals have given rise to fertile hybrids; and 
hence it becomes impossible to say how far their 
varieties may be owing to foreign contamination, 
or to the occurrence of connate varieties in the 
original species. It is, however; useless to in- 
dulge in conjecture where data are defective ; 
but from analogy we might infer that a very 
small part of their varieties have been owing to 
foreign admixture. 
It now remains for us to notice the theory of the 
successive transition of species proposed by M. La- 
marck. According to him, the habits and manners 
_ of life assigned to each animal do not follow from 
any original form peculiar to its species ; but that, 
on the contrary, the form of each species is the 
result of its habits, its manner of life, and other 
| influential causes, which, in the course of time, 
have constituted the shape of the body and the 
parts of the animal. With new forms, new fa- 
culties have been acquired; and thus gradually 
| Nature has produced the animals as we now see 
them. We must in justice remark, that this 
theory has been censured in this country with 
undue severity, from its appearing at first sight 
to dispense with the agency of a First Cause in 
| the creation of the several species of animals. 
| But in reality, a creative power is as indispensa- 
| ble in maintaining the successive transition of 
forms, as in originally creating them. Lamarck 
himself was well aware of this, for he observes, 
| “ When I see that Nature has placed the source 
of all the actions of animals, of all their faculties, 
from the most simple to those which constitute 
|| instinct, industry, and finally reasoning—in their 
| wants, which alone establish and direct their 
| habits ; ought I not to acknowledge in this power 
_ of Nature, that is to say, in the existing order of 
_ things, the execution of the will of its Sublime 
Author, who has imparted them the power?” 
As an illustration of this supposed transition of 
Species, we shall show M. Lamarck’s method 
of explaining upon his theory, how it comes to 
pass that some mammalia can fly. A very an- 
thence had acquired a habit of extending their 
limbs like a parachute. From frequent repeti- 
tions of this act, the skin of their sides became 
gradually enlarged, in course of time, and a 
loose membrane extending from the fore to the 
hind feet, embraced a large volume of air, and 
broke the force of their fall. In a word, they 
acquired the characters of the flying squirrels, 
—Piteronys. These animals, however, were still 
without membranes between their fingers. But 
a race of squirrels of much higher antiquity, 
after undergoing the preceding metamorphosis, 
had acquired a habit of taking still longer leaps 
than the former. Accordingly the skin of their 
sides became more ample, uniting not only the 
fore and hind legs, but even the tail with the 
hinder feet, as well as the fingers with each other. 
These now form our flying lemurs,—Galeopithe- 
cus. ‘There was, however, a third race of squir- 
rels vastly more ancient than any of these, which 
had contracted a habit, in the course of time, of 
extending not only their limbs, but also their 
fingers. From this habit, long preserved and 
become inveterate, they not only acquired lateral 
members, but an extraordinary elongation of the 
fingers of the anterior limbs, with large inter- 
mediate membranes, so that at length they con- 
stituted those singular wings which we find in 
the bats,—Vespertilio. “So great is the power 
of habit,” observes Mr. Lamarck, “ that it singu- 
larly affects even the conformation of the cor- 
poreal parts, that it imparts to those animals 
which have contracted certain habits through a 
long course of ages, certain faculties which other 
animals of different habits do not enjoy.” 
Upon this theory, it was requisite that the 
higher orders of animals should be regarded as ot 
the greatest antiquity, a longer time being neces- 
sary for their transition from those simple forms, 
which were supposed to have been first created. 
“T have no doubt,” proceeds Lamarck, “ that all 
the mammalia have originally sprung from the 
ocean, and that the latter is the true cradle of 
the whole animal kingdom. In fact, we still see 
that the least perfect animals are not only the 
most numerous, but that they either live solely 
in the water, or in those very moist places, where 
Nature has performed, and continues to perform, 
under favourable circumstances, her direct or 
spontaneous generations; and there, in the first 
place, she gives rise to the most simple animal- 
cules, from which have proceeded all the animal 
creation.” —(Philosophie Zoologique, tom. 2, p. 
456). We must remark, that there has never 
yet been, within the historical era, a well authen- 
ticated fact of any animal of one species having 
acquired organs or faculties belonging to an- 
other; nor are any species known to have lost 
any of their senses or powers to make way for 
new ones. It must further be observed that, 
while we have never found any of these transi- 
_ cient race of common squirrels had long amused | tions in circumstances within the sphere of our 
