DIVISION OP ANIMALS. 
75 
to collecting them into a superior order, according as we find ourselves 
conducted to that classification by 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 upon certain liases of divi- 
S10ns , agreeably to which, beings, when observed, are arranged in their 
proper places. 
fhc first mode cannot mislead us ; but it is applicable only to those 
'rings of which we have a perfect knowledge : the second is more ge- 
nerally practised, but it is subject to error. When the bases that have 
J een adopted remain consistent with the combinations which observa- 
1 10 n discovers, and when the same foundations are again pointed out 
J J the results deduced from observation, the two means are then in 
lln ison, and we may be certain that the method is good. On the ana- 
torny of animals, science is most deeply indebted to the learned, acute, 
and indefatigable Cuvier, who has contributed more than all others, 
Uave Hunter,) to our accurate knowledge of the characters on which 
ll to classes arc founded. The whole animal kingdom is by Cuvier 
' lv ided into four great types : — 
1st. That of the animals which have their brain and the principal 
i'to't of their nervous system inclosed within vertebra?, and their mus- 
ries attached to a body skeleton. - Vbrtebrosa. 
2dly. Those that have no skeleton ; whose muscles are attached 
to their skin, and whose nervous system is irregular in its form and 
distribution. - - - r - - - - Mollusc*. 
8dly. Those that have no skeleton ; whose muscles are attached to 
their skin, which is hard, or to processes proceeding from itr and whose 
Nervous system consists of a series of knots or ganglia, brought into 
communication by two longitudinal nervous cords. - Annulata. 
ithly. Those whose bodies are radiated, and in whom no nervous sv- 
, et n has been discovered, and who have but one opening for the recep- 
ll °n and rejection of their food. - - Radi at a or Zoophytes. 
The animals which come under my observations in this work, be- 
on 8 to the type Anmduta, and the classes to which they belong may 
readily he distinguished by the following characters. 
- * Gills for respiration. 
i-togs sixteen : antennae two or four. 
. *• Sacs for respiration. 
e gs twelve : antenna; none : 
*** Trachea for respiration. 
a. No antenna. 
Classes. 
- 1. Crustacea. 
- 3. Araciinoidea. 
- 4. Acari. 
q. h. Ttao antenna. 
fo thoracic legs : abdomen also bearing legs : - 2. Myriapod*. 
Is thoracic and no abdominal legs - - 5, Insect*. 
