no 

 W 



OF MAMMALIA. 231 



134, en, cr) and the organs of sensation (o, n, t) ; the second 

 encloses the heart (//) and lungs (I), and the third, which is sep- 

 arated from the second by a transverse 

 membranous, muscular partition, the di 

 diaphragm, (dp,) is occupied by the 

 stomach, (st,) intestines, (i,) liver, (lv,) a 



kidneys, (k,) spleen, (5,) bladder, (ft/,) l\i%IS<S&J*ft% 

 and the organs of reproduction, (ov, ft, 

 ut, vg). The first, the head, is in great 



part an expansion of the spinal column, 



e ut vg h gn 



(v, va,) under the guise of the skull, rig. 135. 



(sk,) and has appended to it the jaws, (j,) between which and 

 the skull is the mouth, the enclosed tongue, (t,) and the entrance 

 to the throat () and windpipe (e, f). 



The spinal column (v, va, a) consists of a longitudinal series 

 of bones which, as it were, overarch the organs of the chest and 

 abdomen and continue into the tail. Each bone of the series 

 consist of a central portion, the centrum, (v,) and a hollow arch 

 (a) above the latter. Within this arch the great nervous cord 

 (en, cr, nr) runs from the skull, which is the first arch, to the tip 

 of the tail. The ribs and bones of the limbs (b) are lateral ap- 

 pendages of the vertebral column, to which they are attached 

 by ligaments, and upon which they are moved backward and 

 forward by muscles (m) which surround them. We have by 

 this arrangement what appears to be a separation of the body 

 into two distinct superposed cavities, the one containing the 

 centre of the nervous system, and the other the visceral organs; 

 but if now we turn back to the Lancelot, (fig. 133,) I do not 

 think we shall revive any impression of such a state of things 

 existing there. In the latter case we have a mere gelatinous 

 cord (fig. 133, v, v 1 ) underlying the nervous cord (nr, nr 1 ) ; the 



Fig. 135. An ideal foreshortened view of 134, as if seen from behind. In ad- 

 dition to the letters in fig. 134, there are dr, the skin ; ac 1 , the periphery of the 

 abdominal cavity (ac) ; g 1 , the posterior pair of sensory nerves; g%, the anterior 

 pair of motory nerves; c, the glosso-pharyngeal nerve, forming in part the nerve 

 of taste, which is concentrated (at gn) under the tongue. Original. 



