PYTHONS AND BOAS. 



185 



rhomboidal, or X-shaped dark markings ; while the head has a median black line, 

 and the imder-parts are yellowish, with small brown spots on the sides. It is, 

 however, subject to considerable variation, a specimen from Siam in the London 

 Zoological Gardens showing bright yellow lines on the sides. Young specimens 

 show three longitudinal rows of light spots with black edges along the back, 

 Somewhat smaller is the African python (P. sebos), of tropical and South Africa, 

 which attains a length of about 23 feet, and has from eighty-one to ninety-three 

 scales in a row on the thickest part of the body, and only two of the labial shields 



AUSTRALIAN DIAMOND-SNAKE (1 liat. size). 



pitted. This species occurs typically in West Africa, from which region came the 

 specimen represented in the illustration on p. 183 in the act of swallowing a bird; 

 and it was long considered that the South African python or Natal rock-snake was 

 a distinct species. Its colour is pale brown above, with dark brown, black-edged, 

 and more or less wavy crossbars, usually connected by an interrupted or continuous 

 dark stripe running along each side of the back; while the sides are marked with 

 large black spots and small dots. On the top of the head is a large triangular dark 

 brown blotch, which is bordered on each side by a light stripe commencing above the 

 nostril at the end of the muzzle, and passing above the eye; and there is a dark 

 stripe on each side of the head, and a somewhat triangular blotch beneath each eye. 



