CHAr. II.] TlIU CAT'S GENERAL FORM. 15 



The head is rounded, and the jaws arc rather short. The eyes 

 are large, and separated by a considerable interval. The ears 

 become narrow as they ascend, and each stands with its deep 

 concavity directed forwards and outwards. The neck is a little 

 shorter and less voluminous than the head. The front limbs are 

 shorter than the hind limbs, and consist each of an upper arm, a 

 fore-arm, and a paw Avith five short toes. Each hind limb has a 

 thigh, a leg, and a foot with four toes. The proportions of the 

 body are sucli that both the elbow and knee are placed close to 

 the trunk. 



Certain symmetrical relations and contrasts between different parts 

 of the cat's frame are evident on even a cursory examination of it. 

 Thus there is an obvious contrast between its dorsal and its ventral 

 aspect, and this contrast extends along each limb to the ends of the 

 toes. 



Again, there is a resemblance (and at the same time a contrast) 

 between the right and left sides, which correspond with tolerable 

 exactitude one to the other. 



This harmony, termed 'bilateral symmetry, thougli obvious exter- 

 nally, does not prevail in all the internal organs (viscera), Mdiich are 

 more or less unsymmetrically disposed. 



Thirdly, there is a resemblance and correspondence between parts 

 placed successively, as, for example, between the arm and the leg, 

 or between the fore and hind paws ; although this resemblance 

 is less obvious than it might be, owing to the different directions 

 in which the knee and elbow are bent. Such a symmetry is termed 

 serial, and is thus even externally visible ; but it becomes mucli 

 more evident when the animal's internal structure is examined. 

 There we find many successive parts — like the ribs, or the pieces of 

 the backbone — which obviously resemble each other very closely, 

 and so are called by a common name.- Such parts are placed 

 one after another in a "' series," and it is on this account that the 

 symmetry of which they are examples is called serial symmetry. 



If we remove the cat's skin we see beneath it a mass of red flesh 

 — the muscles or organs of movement — and these are divided one 

 from another by delicate membranes. If the muscles be cut away, 

 we come sooner or later to subjacent bones — those of the head, neck, 

 trunk, tail or limbs, as the case may be. The bones of the head, 

 trunk and tail, are the " skull, backbone and ribs." 



If the trunk be cut open, it will be seen that a variety of organs 

 — ^lieart, lungs, kidneys, stomach, intestines, liver, &c. — lie enclosed 

 in a cavity within it. If the skull and backbone be cut through, the 

 "white substance of the brain and spinal marrow will be found within 

 them. Delicate threads of a similar white substance, the )ierves, (which 

 minister to motion and feeling) traverse the body in all directions. 

 as also do a multitude of tubes or vessels, which convey blood to or 

 from the heart. The anterior part of the trunk-cavity (which 

 contains the heart and lungs,) is divided from the hinder portion by 

 a fleshy and membranous partition — the diaphragm. This partition 



