SNAKES 



237 



feet, while at the same time the abdominal scutes, which are connected 

 with the ribs by muscles, 

 are erected and wedged 

 against inequalities of 

 the surface, whereby any 

 sliding backward is pre- 

 vented. In ascending 

 a tree, as it occasionally 

 does, the ringed snake 

 winds itself round the 

 stem, and progresses up- 

 wards in the above-de- 

 scribed manner. (Why 

 do snakes progress with 

 difficulty along a smooth 

 surface ?) 



3. Not merely the 

 limbs, but the pectoral 

 and pelvic girdles also 

 are wanting (slight rudi- 

 ments of the latter are, 

 however, to be found in 

 some snakes). The vertebral column, accordingly, is almost uniform 

 throughout its entire length. 



Vertebra and Ribs of Snake. 



Posterior view; II., anterior view ; Gk., centrum; Gg., con- 

 cave face of centrum ; R., spinal canal ; Ri., ribs ; D., neu- 

 ral spine ; Qu., articular processes (zygosphene and zygan- 

 trum) ; Rg., transverse processes. 



B. Food and the Manner in which it is obtained. 



Like all other snakes, the ringed snake is pre-eminently a predaceous 

 animal. Inasmuch as in its movements the animal's body, along its 

 whole length, is in contact with the ground, a great deal of friction has 

 to be overcome. Consequently, the movements of the animal entail a 

 great expenditure of force. For this reason the snake spends the greater 

 part of its time in repose, and may be described as a relatively slow and 

 aickward animal. Hence, small animals (such as insects, snails, worms, 

 etc.) are not sufficient to supply its wants (why not?), but it is obliged 

 to have recourse to animals of larger size, viz., vertebrates. Its food, in 

 fact, consists of amphibians and their larvae, as well as fish. It is 

 especially fond of frogs. 



1. The ringed snake perceives its prey from a distance by sight. In 

 place of an eyelid, the eye of the snake is covered by a transparent 

 membrane, as the dial of a watch is covered by the glass. Its most 

 developed sense is that of touch. It has its seat in the tongue, which is 



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