Natural-Historical Collections. 295° 
muscular force suggests the necessity of a powerful respiration : and indeed, the 
mole takes care to provide at intervals openings to aérate its burrow. 
It is a very voracious and ferocious animal; M. Flourens has observed that 
hunger destroys it very quickly, and nothing but animal food can satisfy it. No 
individual can pass more than twelve hours without eating ; even after six hours 
abstinence it becomes extremely weak. It generally nourishes itself on worms 
and insects ; but if an occasion is presented of seizing a more important prey, as 
a bird, a little quadruped, or a frog, it jumps upon it with fury, attacks it by 
the belly, devours its entrails, tearing open the wound with its fore paws, and al- 
ways advancing anteriorly in the body, without being stopped either by the pre- 
sence of man or by any noise which may be made to frighten it; it does not 
even spare its own species ; if two be put together without food, the weakest will 
be devoured between night and morning; its very bones will have disappeared, 
and nothing will be found but the skin, slit along the belly. 
Of all the families of mammalia, that of which naturalists have of late disco- 
vered the greatest number of new species, and in which they have determined the 
most differences calculated to form generic and sub-generic divisions, is certainly 
the Cheiroptera or Bats. Almost as many species have been distinguished here- 
in as in the rest of the class. The genera of which the first outline was propo- 
sed by MM. Geoffroy and Cuvier in 1796, have, since that time, been perfected 
and multiplied, especially by M. Geoffroy St. Hilaire senior. MM. Temminck, 
Desmarest, Paul Savi, Fred. Cuvier, Leach, and others, have been equally labo- 
rious, enriching this family with their contributions. 
Very recently, M. Isidore Geoffroy has presented a memoir upon the frugivo- 
rous cheiroptera, which may at present be all comprised under the genus Ptero- 
pus. 
Every one knows that organized beings, torn by man from their natural abodes, 
and submitted by him to new conditions of existence, undergo very considerable 
modifications in their size, their colours, and in some details of their form, espe- 
cially in the integuments,—modifications, however, which are limited, and which, 
at least in the present state of the globe, are confined within very narrow bounds. 
Analogous modifications are also found in those beings, which, though not under 
the subjection of man, have been transported into circumstances different from those 
of their first abode, and yet are not sufficiently dissimilar to destroy the race. But 
modifications of this kind are much less marked than those which spring from the 
agency of man; and no savage species, to whatever distance it may extend it- 
self, indicates any approach to what we see in domesticated animals, in dogs, for 
instance, in oxen, or in sheep. We have been much occupied with these varia- 
tions in animals, produced by domesticity, and naturalists have attempted to 
trace the different degrees, as far as the history of the species has enabled them ; 
but there is another kind of modifications, not less interesting to study,—those 
which domestic races undergo, when, abandoned ‘by ‘man and restored to their 
primitive liberty, they betake themselves again to their savage mode of: life, and 
sustain themselves, conformably to their natural tastes, as far as the country, 
in which they were placed, will permit of the return. 
These are subjects which Dr. Roulin has investigated in the animals which 
the Spaniards have transported to South America, and which live there a savage 
Jitess 
M. G. Cuvier has obtained from the noble collection of Latin classics of M. 
Lemaire, some explanations of the books of Pliny, where there is doubt as to the 
animals; his object has been to determine the species of which Pliny has in- 
* As the Memoir of Dr. Roulin has already been translated into our lan- 
guage, and may be found in the Edin. New Phil. Jour ne Ocr. 1629, p. 326, we 
abstain from presenting it to our readers. 
