That the Linnwan system is exposed to numerous and well grounded objections, and that in many instances it disregards, anatomical structure, which should form the basis of a natural classification, will be readily allowed by the most sanguine admirers of its illustrious author. Yet it must be remembered, that the general adoption of this method renders it desira ble to deviate from it in as few instances as possible ; since the introduction of new orders and names must necessarily create difficulty and confusion in the study of the science. The French zoologists, whose successful labours in the advance ment of natural history must be acknow ledged with every due tribute of respect, have carried the rage of innovation too far, in the universal rejection of the Lin nman method, and the unnecessary multi. plication of new orders and genera. The defects or errors of any system could not cause so much perplexity and inconve nience, as the want of a generally receiv ed standard, and the unlimited licence, in which every individual indulges, of fabricating new classifications and arrange ments. To judge by some recent works, we should be led to suppose, that the merit of a systematic arrangement of ani mals does not consist in the simplicity or intelligibility of the system ; but is in proportion to the number of newly-creat ed terms.
Animals may be distributed into two grand divisions : those which have a ver tebral column, and red blood : and those which have no vertebra, and are white blooded.
In the former division there is always an interior skeleton ; the chief support-of which is the column of vertebra, a spinal marrow contained in the vertebral canal ; never more than four members, of which one or both pairs are wanting in some instances. The brain is contained in a cranium : there is a great sympathetic nerve ; five senses; two moveable eyes ; and three semicircular canals in the ear. The circulation is performed by one mus cular ventricle at least. There are lym •phatic as well as blood vessels. The jaws being placed horizontally, the mouth is opened by their moving from above down wards, or from before backwards. There is a continuous alimentary canal, ex tending from the mouth to the anus, which is always placed behind the pelvis; peritoneum; liver, spleen, and pancreas ; two kidneys, and renal capsules ; and two testicles.
The vertebral animals are subdivided into warm and cold-blooded.
Warm blooded vertebral animals have two ventricles in the heart, and a double circulation ; and breathe by means of lungs. The cranium is completely filled by the brain. The eyes are closed by eye lids. The tympanum of the ear is hollow ed out of the cranium, and the labyrinth is excavated in the bone. Besides the semicircular canals, the has a coch lea. The nostrils communicate with the
fauces, and allow the passage of air into the lungs. The trunk is constantly fur nished with ribs.
In cold blooded vertebral animals, the brain never entirely fills the cranium. The eves seldom possess moveable eye lids. When the tympanum exists, it is on a level with the surface of the head. There is no cochlea. The different parts of the ear are connected but loosely to the cra nium.
The division of warm blooded ani mals contains two classes ; alammalia and Birds.
The r6mmalia are viviparous, and suckle their young, from which circum stance the name is derived. They have an uterus with two cornua : and the male has a penis.
There are two occipital condyles, con necting the head to the atlas : never less than six, nor more than nine cervical ver tebrx: a very brain ; four ossictila auditus, and a spiral cochlea. The skin covered with hair. A muscu lar diaphragm separates the chest and abdomen. There is an epiglottis. The lower jaw only moves. The fluid in the lacteals is white, and passes through several conglobate glands. There is an omentum.
Blumenbach establishes the fqowing orders in this class : 1. Bimanum. Two handed. Genus 1. Homo.
H. Quadrumana, four handed animals; having a separate thumb, capable of being opposed to the other fingers, both in their upper and lower extremities. Teeth like those of man, except that the cuspidati are generally longer.
1. Simiz, apes, monkey* baboons.
2. Lemur, macauco.
III. Bradypoda, slow-moving animals 1. Bradypus, sloth.
2. 1lyrmecopliaga, ant-eater.
3. M anis, scaly-lizard, or pangolin.
4. Disy pus or Tau), armadillo.
This order forms two in the arrange ment of Cuvier. 1st. Tardigrada ; which includes the sloths. There are no inci sores in either jaW ; there is a complicated stomach, but no rumination. 2dly. Eden tata, toothless animals. Some of these have no teeth ; others want the incisores and cuspidati. The tongue is long, slen der, and projectile, for seizing the in sects on which the animals feed ; body covered with hard substances. The ar madillo, manis, ant-eater, and ornithor hyncus, or duck-billed animal, belong to this order.
IV. Cheiroptera, having the fingers elongated for the expansion of a mem brane which acts as a wing.
Vespertilio, bat.
V. Wires. Rodentia of Cuvier-gnaw ing animals. Have two long and very large incisor teeth in each jaw, by which they cut and gnaw hard bodies, chiefly vegetables ; there is a large interval be hind these teeth, unoccupied by cuspi dati; long intestines, and generally a large cmcum. The hind legs, being longer than the front extremities, give to these ani mals a leaping mode of progression. The disproportion is sometimes so great, that the front legs are not used in walking. A bone in the penis.