1NSECTIVOUA. 



999 



The cervical portion of llic serrutus in 

 is simple, rM essively thick and swellin 



in U only to the jxistcrior vertebra;. The 

 trnpi :ins consists only of two bund:' 

 fleshy fibres, winch aii~c IVoin the lumbar ver- 

 tcbr.r, and are inserted into the posterior ex- 

 tremities of the long and narrow scapnhu; and 

 as these fasciculi arc nearly parallel, their 

 action would be rather to separate than to ap- 

 proximate the posterior parts of these bones, 

 were it not for a strong transverse ligament 

 which holds them together. Their application 

 consists in moving the anterior part of the body 

 upwards. The scapular attachments of the 

 r/i/iiii/Hiiiliits are principally to this transverse 

 ligament of the two scapulae, and as it is in- 

 serted into a sort of ossified modification of a 

 cervical ligament, its office consists in raising 

 tin head with ', r ivat force. The levatiir scapula 

 is wanting; its existence would be obviously 

 useless. The /ifi-tcni/is minor is very slender; 

 it is attached to the anterior parts of the first 

 ribs, and to the ligament, already mentioned, 

 which joins the clavicle to the scapula. There 

 arc also two muscles arising from the anterior 

 part of the sternum, and inserted into the large 

 Mad of the clavicles. 



The most important muscles of the humerus 

 are the pecluruia majnr, the latissimia dorti, 

 and the tcrcs mujor, all of which are of great 

 size ; and it is by means of these muscles that 

 the astonishing efforts of the animal are made 

 in excavating his passages, and throwing the 

 earth behind him. The pectoralis major is of 

 extraordinary thickness. It is formed of six 

 portions, which are all of them inserted into 

 the broad quadrate portion of the humerus. 

 Four of these portions arise from the sternum, 

 the fifth from the clavicle ; and the sixth passes 

 across transversely from one arm to the other. 

 The lutixshiitis I/<T.<I is also of considerable size, 

 and is inserted into the posterior surface of the 

 quadrate portion of the humerus. The ttres 

 major, which is of enormous thickness, is in- 

 serted near the former muscle. 



The other muscles of the anterior extremity 

 do not require particular description. 



There is one peculiarity in the muscular sys- 

 tem which deserves special notice; it is the 

 enormous development of the i>niitiiculus tur- 

 nouts in the hed^ehou, by which it is enabled 

 to roll itself up in a ball with such astonishing 



force as to afford with its spiny covering .1 

 complete pinii-i tion against its mo-t poueifnl 

 antagonists. I proceed to describe this ap- 

 paratus and its nsi-s. 



As this muscular apparatus has no attach- 

 ment but to the skin, it changes its position 

 with every movement of the integument ; and 

 it is therefore necessary to consider it under 

 the various relations which it assumes in the 

 different positions of the animal. Considering 

 it then, in the first place, as rolled up in a ball 

 (jig. 447), either for defence or during repose, 



Fig. 447. 



the whole body is enveloped beneath the skin 

 by a strong sac or covering, consisting of a 

 mass of fleshy and concentric muscular fibres, 

 of an oval form. All these fibres are attached 

 intimately to the skin, and even to the base of 

 the spines with which it is every where furnished, 

 so that it is even difficult to detach the fibics in 

 dissection. The thickest part of this fleshy sac 

 is at the lower margin or mouth of the sac, 

 at which part it forms a sort of sphincter, com- 

 posed of orbicular muscular fibres. On the 

 other hand, when the hedge-hog is unrolled, 

 and at its full length (Jig. 448), the muscle in 

 question totally changes its figure and relations. 

 The muscle now lies over the back, forming an 

 oval covering, the middle of which is very tlnn, 



Fig. 448. 



