114 BRITISH LIZARDS 



tion. Given a fracture at any point, one may say 

 with certainty where any other fracture may occur, by 

 simply counting the scales ; the other fractures will 

 be only at the ends of the rows of scales numbering 

 2, 4, 6, 8, 10, and so on, from the first fractured 

 point. It should be added that the explanation here 

 offered to account for the fragility of the tail is not an 

 accepted view, but it is one which any observant field 

 naturalist can examine for himself on the first slow- 

 worm he encounters. 



It is quite obvious that no special arrangement 

 of ossification in the vertebrae would be sufficient to 

 account for the phenomenon, unless some highly 

 specialised form of muscular and scale structure also 

 existed. Lack of ossification in a bone may be a 

 cause of fracture ; it will not account for a limb or an 

 appendage dropping oh" from the body, as do the tails 

 of some lizards. 



