THE SNAKES 221 



ninw and the Boince. It is a common idea that pythons 

 may be told from boas by the presence on the labial 

 plates of the former of a series of pits. This rule does 

 not altogether hold good. Though the greater number 

 of pythons have these pits and so prommently devel- 

 oped they would seem to be of some functional value, 

 it should be explained that some species of boas also have 

 the labial pits, which, in the genera Epicrates and Coral- 

 lus are as sharply pronounced as among the pythons. 

 An example of the latter genus is the Yellow Tree Boa, 

 Corallus cookii, a life-sized head of which is shown in 

 a photograph. The real structural differences between 

 the pj^thons and the boas relate to the bones of the head 

 and the arrangement of the head plates ; neither are any 

 too definite in separating the two subfamilies. 



With the exception of one small species, found in 

 Mexico, the members of the Pythonince are confined to 

 the Old World; the Boince occur in both Hemispheres. 



In the Pythonince we find a great variety of forms, 

 among them the king of the big constrictors, the Regal 

 or Reticulated Python, P. reticidatus, called by the 

 Malays the Ular-Sawa. A friend of the writer, much 

 interested in serpents, whose observations are always 

 calm and reliable, measured a dead specimen of this 

 species that lacked a few inches of being thirty feet long. 



The pattern of this splendid snake is difiicult to put 

 into words. It consists of an interweaving of rich yel- 

 low, brown and black like Oriental tapestry combined 

 with an iridescence glowing in all the high lights of the 

 folds. The markings on the head at once separate this 

 snake from the other great Indian python, P. molurus: 

 for the head of P. retimlatus is uniform brown with a 

 narrow black line from the snout to the base ; P. molurus 

 has a blotch between and in the rear of the eyes shaped 



