l4 AUSTRALIAN SNAKES. 



adapted to every variation of ground over which 

 they move, yet all the varieties of their locomotion are 

 founded on the following simple process. When a 

 part of their body has found some projection of the 

 ground which affords it a point of support, the ribs, 

 alternately of one and the other side, are drawn more 

 closely together, thereby producing alternate bends of 

 the body on the corresponding side. The hinder 

 portion of the body being drawn after, some part of it 

 finds another support on the rough ground or a 

 projection ; and the anterior bends being stretched in a 

 straight line, the front part of the body is propelled in 

 consequence. During this, peculiar kind of locomotion 

 the numerous broad shields of the belly are of great 

 advantage, as, by means of the free edges of those 

 shields, tliey are enabled to catch the smallest projections 

 on the ground which may be used as points of support. 

 A pair of ribs correspond to each of these ventral 

 shields. The snakes are not able to move over a 

 perfectly smooth surface." The smooth surface does 

 not mean a boarded floor, or even one covered with 

 oilcloth, for I have found that snakes progress tolerably 

 well, but not so rapidly, on this substance as on the bare 

 ground. On a glass sheet, however, which is without 

 projections, a snake is helpless, as far as progression is 

 concerned — its movements then consist of what has 

 been termed " rapid wriggles," and may be likened 

 to the peculiar motions of the mosquito larva, or 

 rather the Bloodworm (^Chironomus), in water, When 



