2 JNVERTEBRAL ANIMALS. 



The animals of this division are but feebly endowed with the 

 functions of relation. Many of them indeed, almost deprived of 

 locomotion or fixed to other bodies, have neither choice of situa- 

 tion or food, but remain for their term of life in the places where 

 they originally had their birth. But the want of intelligence 

 is largely made up to many classes of this division, by their su- 

 perior instinctive powers, which, in as far as regards their subsist- 

 ence and reproduction, surpasses that of the vertebral animals. 

 In one very large class, the Insects, this instinctive intelligence 

 is displayed in a very striking manner, in the combination of 

 individuals for one common purpose, and in the wonderful sub- 

 sidiary arrangements of their little commonwealths. 



It has been observed, as a distinction between the vertebral 

 and the invertebral animals, that while in the former the bones 

 or hard parts are more or less formed of phosphate of lime, the 

 hard parts of the latter, such as the shells of the Mollusca and 

 Crustacea, and the stony matter of corals and madrepores, are 

 chiefly composed of carbonate of lime. 



The Invertebral Animals, as noticed in the introduction, are 

 arranged by Cuvier into three great divisions. 1. Those which 

 have no skeleton ; in which the muscles are attached only to the 

 skin, which forms a soft contractile covering ; in which the ner- 

 vous system, composed of scattered masses, is contained in this 

 general envelope ; in which there is a complete circulating sys- 

 tem, particular organs for respiration, and organs for diges- 

 tion and secretion, are termed MOLLUSCA. 2. The second di- 

 vision, including those animals in which the trunk is divided 

 transversely into a certain number of rings, and of which the 

 integuments, either hard or soft, have always the muscles at- 

 tached to their interior, is named AUTICULATA. The nervous 

 system in this division consists of long threads, running along 

 the belly, and thickened at certain distances into knots or gan- 

 glions ; and the body is in most cases provided with jointed 

 members or legs at the sides of the annular segments. Their 

 jaws, when they have any, are always lateral. 3. The third great 

 division includes all the animals known under the name of 

 Zoophytes, to which Cuvier gives the name of R ADI AT A. In 

 the preceding divisions the organs of movement and sensation 

 are dispersed symmetrically on the two sides of a common axis. 

 In the present they are arranged circularly around a common cen- 



