

DIVISIONS OF THE ANIMAL KINGDOM. XXVII 



entangle their victims. Amongst these are the Sepiae termed 

 uttle-fish, which have the property of emitting an inky fluid, 

 either to conceal themselves from their enemies, or permit 

 them to approach their own prey. 



In all the kinds of animals enumerated, no brain, pro- 

 perly so called, exists, the rudiments of it merely appearing 

 in ganglia, or knots of nervous filaments. Now, the nervous 

 system is the instrument by which the knowledge of external 

 objects is conveyed to the sentient being, and by which the 

 ictates of the will are transmitted to the various organs of 

 the body. In proportion to its development, the animal rises 

 higher in the scale of living beings, and is endowed with 

 more varied powers. In the lowest tribes of all, it is merely 

 developed in bundles of fibres, surrounding the alimentary 

 canal ; ascending higher, it forms knots or ganglia, and still 

 higher, it changes its place, and expands towards the head, 

 and stretches along the dorsal region. In the highest order 

 of animals of all, it enlarges into a true brain, and, extending 

 along the back, is inclosed in numerous bones termed vertebrae. 

 The Vertebrata. or animals possessed of vertebrae, are 

 usually divided into four groups, which may be termed sub- 

 kingdoms. 



1. Pisces. 



2. Reptilia. 



3. Aves. 



4. Mammalia. 



All the Vertebrata have a series of bones moveable upon 

 ne another, and bound together, termed the Spine. Each 

 rtebra has a perforation through it, so that, when the whole 

 ertebrse are joined together, a long continuous canal passes 

 hrough the spinal column. At the upper or anterior termi- 

 nation of the column, the vertebrae change their form, become 

 flat, and, being fixed together, form a rounded cavity termed 

 the Cranium ; connected with which, but distinct from it, are 



fe bones of the face, in which are the receptacles of the special 

 nses, namely, sight, smell, hearing, and taste. The era- 



