no BRITISH LIZARDS 



ventral. Diag-rammatically, the positions of the eight 

 muscles may be thus represented — 



Dorsal Muscles. 



Lateral Muscles. jf '^ Lateral Muscles, 



Ventral Muscles. 



Fig. 1. 



The two dorsal muscles are separated from each 

 other by a somewhat wider interval than any of the 

 others, so that they are, strictly speaking, dorso-lateral, 

 the dorsal median line being free from muscle. 



The relative shortness of the two ventral muscles 

 accounts for the fact that the fracture begins on the 

 ventral side and is easiest here. 



The thick end or attached end of these muscles is 

 very firmly inserted into the inner layer of the integu- 

 ment. The thin tapering end lies practically free in 

 the sheaths provided for its reception. After all, this 

 is the only arrangement which would permit of that 

 easy fragility of the tail under consideration. It is 

 impossible to fracture the tail opposite the points of 

 origin of these muscles in the integument ; any attempt 

 to do so results in their separation where the ends 



