2G9 



Vegetative or Organic Life ; the brain, nerves, eye, ear, and muscular system, 

 of Animal, or Nervous Life. 



The two Kingdoms being thus discriminated, the study of the resemblances 

 and differences presented by Animals has led to the division of the Animal 

 Kingdom into various groups ; on the ground that all the members of each 

 group, in certain points, resemble one another, and differ from the members 

 of other groups. The primary divisions are named Sub-Kingdoms. Each 

 Sub-Kingdom is divided into Classes, the Classes into Orders, the Orders 

 into Families, the Famdies into Genera. The ultimate Sub-Division is of 

 Genera into Species. 



The Animal Kingdom is now usually divided into Five Sub-Kingdoms, 

 each under a title, more or less descriptive of some obvious and leading 

 peculiarity of structure. The Vertebrata form the highest Sub-Kingdom ; so 

 named from the possession of a backbone, or spine, composed of a variable 

 number of small bones, called Vertebrae — as examples of each of its four classes, 

 take the Horse, the Eagle, the Crocodile, the Salmon. The title of the Second 

 Sub-Kingdom, Articulata, indicates that it comprises Animals, whose bodies 

 are composed of a succession of segments, arranged in a line — hence called 

 jointed, or articulated, animals— of which peculiar structure the Bee and the 

 Lobster are well known forms. All the insect tribes belong to this Sub- 

 Kingdom. The Third Sub-Kingdom comprises the Mollusca, so named from 

 the softness of their bodies ; some, but not all, of these Creatures are protected 

 by a shell. The Slug and Oyster are both Molluscs. The Radiata compose 

 the Fourth Sub-Kingdom ; and take their designation from the radial or star- 

 like symmetry of their bodies. This form, Carpenter remarks, must in itself 

 be regarded as a Vegetative character, for it corresponds with that which is 

 seen in the disposition of the appendages around the axis in the leaf-buds and 

 flower-buds of Plants. The Star-fish and Sea- Anemone are characteristic forms 

 of the Radiata. The Fifth Sub-Kingdom contains the Protozoa, so called as 

 being the first and lowest form of Animal Life, corresponding in rank with 

 Protophytes in the Vegetable Kingdom. Infusoria and Sponges are members 

 of this group.* 



Now, in determining the priority and mutual relations of these great groups, 

 and of their sub-divisions, we must keep in view the principle of Animal 

 Perfection already announced ; namely, the degree of Nervous Life accorded 

 to each, and displayed in the faculties of sensation and locomotion; and, finally, 

 in the mental attributes of Intelligence and Will. An animal is high in the 

 scale, as it recedes from, low as it approaches, a mere Vegetative Life. In 

 other words, the more it is endowed with Nervous Life the higher is it to be 

 placed on the scale of Animal Existence. Tried by this test, we find the 

 Protozoa scarcely entitled to rank as Animals. No definite trace of a Nervous 

 System has yet, I believe, been discovered in them ; and their claim to be 

 reckoned Animals rests chiefly upon the nature of their food, which consists of 

 Organic substances ; (whereas, Plants are enabled to assimilate mineral sub- 

 stances ;) and upon their performance, after a strange fashion of their own, of 

 the function of digestion. 



It is not untd we reach the higher Radiata that we find the first definite 

 indications of a nervous system. Every segment, or division, of these 

 creatures is connected with a ganglionic centre ; a ganglion being a little 

 swelling lump or knot of nervous substance ; and this centre seems subservient 



* Cuvier made only four sub-kingdoms. But bis lowest division, Badiata, comprises 

 so heterogeneous an assemblage of forms, that later Naturalists have broken it up, and a 

 portion of what Huxley has called the "Radiate Mob" of Cuvier, is now classed as a 

 distinct sub-kingdom, under the title of Protozoa . The arrangement, like every other 

 part of merely physical science, must continue to vary with increasing knowledge. 



