DIVISTON or ANIMALS. 75 



to collecting them into a superior order, accord in 2; as we find om-selves 

 conducted to that classification hy a view of the whole of their attri- 

 butes. The second, and that which the greater part of modern natu- 

 ralists have employed, is to fix beforehand ujion certain bases of divi- 

 sions, agreea!)ly to which, beings, when observed, are arranged in their 

 proper jilaces. 



The first mode cannot mislead us; but it is applicable only to those 

 beings of which we have a pcri'cct knowledge: the second is more ge- 

 nerally practised, but it is subject to error. When the bases that have 

 been adopted remain consistent with the combinations which observa- 

 tion discovers, and when the same foundations are again pointed out 

 by the results deduced from observation, the two means arc then in 

 unison, and we may be certain that the method is good. On the ana- 

 tomy of animals, science is mostdec]ily indebted to the learned, acute, 

 and indefatigable Cuvier, who has contributed more than all others, 

 (save Hunter,) to our accurate knowledge of the characters on which 

 the classes are founded. The whole animal kingdom is by Cuvier 

 divided into four great types :— 



1st. That of the animals which have their brain and the principal 

 part of their nervous system inclosed within vertebra, and their mus- 

 cles attached to a bony skeleton. . _ _ - Vlrtebkosa. 



2dly. Those that have no skeleton; whose muscles are attached 

 to their skin, and whose nervous system is irregular in its form and 

 distribution. ________ Molltjsca. 



3dly. Those that have no skeleton ; whose muscles are attached to 

 their skin, which is hard, or to processes proceeding from it; and whose 

 nervous system consists of a series of knots or ganglia, brought into 

 communication by two longitudinal nervous cords. - Anmlata. 



4thly. Those whose bodies are radiated, and in v, bom no nervous sy- 

 stem has been discovered, and who have but one opening for the recep- 

 tion and rejection of their food. - - Kadiata or Zoophytes. 



The animals which come under my observations in this work, be- 

 long to the type Annuhiia, and the classes to which they belong may 

 readily be distinguished by the following characters. 



* Gilh for reap I rat km. C!(isf:es. 



Legs sixteen: antennae two or four. - - 1. Crlistacea. 



** Sacs for respiration. 

 Legs twelve: antenna- none : - - - 3. Arachnoidea. 



*** Trachcicfor respiration. 



a. JVo untcnncE. 



. - - A. ACART. 



b. Two antennte. 



Six thoracic legs : abdojnen also bearing legs: - 2. Myrtapoda. 

 Six thoracic and no abdominal legs - - 5. Insecta. 



