38 
FIRST CLASS OF THE VERTEBRATED ANIMALS. 
nature of their food ; others agree with the Rodentia in these particu- 
lars, and others again with the Edentata. 
THE CNGUEATE0 MAMMALIA. 
The animals with Hoofs are less numerous, and at the same time less 
various in their structure. 
7. Pachydermata, or Jumenta, comprise all the hoofed animals which 
do not ruminate. The Elephant, though included in this class, would 
properly form a class of itself, which is allied to the Rodentia by some 
remote analogies. 
S, Rusiinantia. — The Ruminating animals form a veiy well-marked 
order, from their cloven feet, their four stomachs, and the absence of 
true Incisors in the upper jaw. 
THE SEA-EEASTS. 
9. Cetacea Finally, we arrive at the Mammalia altogether desti- 
tute of hinder extremities. From their partaking of the form of the 
Fishes, and their aquatic life, we should be led to constitute them a 
separate class, did not the remainder of their economy resemble the 
Mammalia in every respect. These are the Fishes with warm blood of 
the ancients [the Sea-Beasts of the present day], which unite the strength 
of the othe'r Mammalia to the advantage of being sustained by the watery 
element. It is accordingly in this class that the most gigantic animals 
are found. 
The characters upon which these orders are founded will be seen more clearly in 
the following Analytical Table: — 
DIVISION OF THE CLASS MAMMALIA INTO NINE ORDERS. 
CLASS I MAM.MALIA. 
CONTAINING MAN AND BEASTS, WITH WARM BLOOD; HF.ART WITH TWO VENTRICLES; FEMALES SUCKLING THEIR YOUNG WITH MILK, SECRETED IN BREASTS 
OR MAMIDE; VIVIPAROUS, EXCEPTING THE MONOTREMATA, WHICH ARE EITHER OVIPAROUS OR OVO-VIVIPAROUS. 
Orders 
With nails or claws. 
Limbs Four, • 
I Without Marsupial bones. 
[With Marsupial bones, 
„ f With less than four stomachs. 
With hoofs, J , . 
L [ With tour stomachs. 
Limbs Two, 
r With two hands. 
• 
1 . 
Bi.mana. 
With three kinds of teeth, 
^ With four hands. 
• 
. 2. 
Quadrumana. 
< 
(. Without hands. 
, 
3. 
Carnassiers. 
Without canine teeth. 
« • • . 
. 
. 4. 
Rodentia. 
, Without incisors, 
« 
5. 
-Edentata. 
6. Marsupialia. 
7. Pachtdermata, 
8. Ruminantia. 
9. Cetacea. 
GENERAL REVIEW OF THE MAMMALIA. 
External relations of the Mammalia to the other Classes, and to each other, — Usage 
of the terms Mammalia, Beast, Quadruped, Bimanous, Quadruinanous, and 
Cetaceous. — Further subdivision of the Mammalia into Families and Tribes. 
In the preceding outlines, the internal oi'ganization of the ULuumalia, and the leading 
principles of their classification, have been briefly explained. We shall now proceed 
to consider, in a general manner, their external relations to the temaining classes of 
animals and to each other. 
In those saperfleial characters, which strike the observer most forcibly at first 
sight, the Mammalia present many traits which aro to he found equally in the 
odior Classes, a fact which is not sufficiently adverted to in ordinary discourse. Thus, 
by tlic term Beast or Quadruped, it is usual to understand an animal covered with 
hair, and having four feet; and whenever a Bird or a Fish is referred to, the feathers 
of the former and the scales of the htter olfer themselves readily to the imagination. 
Yet these external characters by no means serve to distinguish the several classes of 
Vertebrated xknimals. The property of having four feet, which is possessed by a 
large and unportant portion of the Mammalia, is not confined solely to them. Many 
oviparous animals belonging to the Third Class ("KepIiVioJ possess the same character- 
istic; and in this respect the four-footed Beasts of the earth, which approach Man so 
nearly in their other characters, and occupy so high a place in the economy of N ature, 
are not superior to the Lizards and Frogs. Again, the Armadillocs (Dasijpus), 
instead of being covered with liair, are armed with a solid covering like the Tortoises, 
or even like the Crustacea. The animals of the genus Mauis are covered with scales 
not very different from those of the Fishes, and the same structure is found in the 
tail of the Beaver (^Castor Fiber.) The Porcupines (Hgstrix), and the Hedgehogs 
(Erinaceus), aro covered with a species of sharp quills, without feathery fibres on 
the extremity, but having the tube very like that of Birds. The Cetacea, or Sea- 
beasts, resemble the Fishes so forcibly in their external forms, that the uninformed 
portion of mankind persist in calling them Fishes in opposition to the universal deci 
sion of Naturalists. The Whale, Dolphin, Grampus, and other animals of this order, 
have nothing in common with the Fish, except the civcnmstanccs of their living in 
the same clement, in being destitute of hair, and in possessing that external form 
necessary for rapid motion in a fluid of considerable density. Yet the term MTiale- 
fishery will long preserve its usage among that numerous class of persons, who are apt 
to reject the critical observations of Naturalists, from their apparent over-refinement. 
• Nahire appears to evade, by the variety of her combinations, those obvious divisions 
which a superficial examination would lead us to form; and the Mammalia approach to 
the Birds, the Reptiles, the Fishes, and even the Crustacea, in the character of their 
external covering. This variety in the .superfioul appearance establishes clearly the 
necessity of seeking, in their internal organization, for the principles of classification. 
It has often been stated, that while Error lies on the surface. Truth must he sought 
deeply in the hidden parts ; and this assertion, which is only made mctaphoricaliy la 
reference to moral subjects, is literally true in Natural History. 
The Birds share their quills with the Hedgehogs atid Porcupines; and their long 
bills destitute of teeth, with their tongue, aro imitated by the trunk and tongue of the 
Aut-caicrs (Myrmecophaya.) The Reptiles are not alone armed svith a solid cover- 
ing. The Fishes share their scales with the Beaver and Manis, and their fins with 
the Seals (Phoca), the Morse (Tricheehus), the JIanatus, and the true Ceta- 
cea. The Birds have their powers of flight assigned also to the Bat; the crawling 
of the Reptiles and Eels is imitated in some degree by the slow movements of the Sloth 
(Bradypus) ; and the Fishes .share their powers of swimming with most Mammalia, 
but more especially with the tribe Amphibia, and order Cetacea. 
As the meanings of the terms Beast, Bird, Fish, and Quadruped, arc established by 
popular usage alone, they are necessarily destitute of that precision which should 
characterize the language of science. The term Mammalia, which has been gene- 
rally adopted by Naturalists, is much more wide in its signification than that of Quad- 
ruped; it agrees more nearly with the word Beast than perhaps any other term, 
although not exactly, as the latter term excludes Man, and the Cetacea are not always 
understood by the vulgar to be really Sea-beasts. The term Quadruped is still more 
improperly considered as synonyraons with Mammalia, with whiti, however, it is 
often confounded. In the last-mentioned class Man is included as well as the Cetacea, 
although he is a Biped, and they are altogether destitute of hinder limbs. The Ape 
tribes arc posse.»sed of four hands, and properly Quadrumanous. Even of those ani- 
mals which are, strictly speaking, Qu,adrupeds, from their walking habitually on four 
feet, many either frequent the water or are capable of supporting themselves in the 
air. The Seals and other Amphibia, although Mammalia, cannot properly be styled 
Quadrupeds, and the same observation applies to the Bats. 
The true Quadrupeds live exclusively on the land ; they may bo said to divide it 
with Man, whoso Nature they approach more nearly than that of the Birds, Reptiles, 
or Fishes. Bat we must observe that the term quadruped strictly supposes that the 
animal walks on four feet. If it be destitute of feet like the Maiiatus and true Ce- 
tacea, if it bo supplied only with arms and hands like the Ape, or if it possess wings 
like the Bat, the term Quatlrupcd ceases to be applicable. Man is the only Biped 
and Bim.anoas animal, because he alone possesses two feet and two hands ; the Mana- 
tus is only Bimanous, and the Bat is a Biped, while the Ape is Quadrumanous or 
four-handed. The Jerboas (Dipus), and Kangaroos (Macropus), cannot itropcrlj 
be styled Quadrupeds, because they can walk only on their hind-feet, in oonsequeneo 
of the fore-limbs being too short and weak. The signification of tiic term Quadru- 
ped is further restricted by removing all those animals which are able to use their 
fore-paws as a substitute for hands, such as the Bears ( Ursus), the Marmots (Arc- 
tomys), the Coatis (Nasua), the Agoutis (Dasyprocta), the Squinels (Sciurus), 
and the Rats (Mm); and those last-mentioned animals form a kind of intermediate 
class between the Quiulrupeds .and the Quadruinanous tribes. The term Quadruped is 
thus applicable only to one half of the Mammalia: it is totally inapplicable to at least 
one quarter, and is not strictly .applicable, in its full extent, to the remainder. 
The Quadrumana fill up the link which would .separate the form of Man from that 
of the Quadrupeds. Those auimal.<, with true clavicles, form another subordinate link 
between the Quadrumana and Quadrupeds; while the Bipeds with wings lead us tn 
the Birds. None of the vague terms of ordinary discourse correspond exactly 'sitk 
those nice distinctions which the philosophical student loves to trace m the works of 
Nature. 
As it is the leading design of classification to assist tho memory by a clear anJ 
lucid arrangement of Natural objects, it frequently becomes necessary to multiply suk' 
divisions in a few orders, which would be altogether superfiuous in the remainder. W 
this contrivance wo are enabled to arrive at general views in every department of 
Nature, and to remember a vast ma.s8 of phenomena not otherwise attainable. These 
subordinate divisions are termed Families or Tribes, and aro determined either bj 
some general resemblance prevailing throughout that whole department, or else by 
some particular character possessed by all the individuals included therein. Ik® 
