SNAKES 



113 



having large and irregular shields on the anterior half of 

 the head, which, in the Boas, are mostly small or broken 

 up into scales. The teeth are large and much recurved. 

 The tail is, v^ith a few exceptions, prehensile. 



The large Boas and Pythons are often said to fast for 

 a considerable period after a heavy meal. Mr. H. N. 

 Ridley, writing of the Pythons in the Botanical Gardens 

 at Singapore, states that the small-sized snakes feed 

 usually once a month, while the larger ones, of about twenty 

 feet, usually once in six to nine months. One which was 

 twenty-two feet long, not long after it was brought to the 

 gardens, passed the remains of a deer. It fed again some 

 time later on three chickens, and abstained from food for 

 six months, when it passed the remains of the fowls, and 

 then ate a good-sized pariah dog, which lasted it for nine 

 months. The experiences of Prof. Vaillant, of the Jardin 

 des Plantes in Paris, do not quite coincide with those of 

 Mr. Ridley, a twenty-one-foot long Anaconda, upon which 

 he kept observation for six and a half years, feeding during 

 this period on only thirty-four occasions, an average of five 

 times a year. The table below shows how my experience 



