Fig. 89. — The internal organs of a Puff Adder {Bilis arietain;). (i) Figure on the left, the lung. The 

 dark line running down over the surface is the windpipe (A). The tube opens into lung-sac on under 

 surface. Higher up at B is topof lung. C isentrance to the windpipe. D is the extended portion which 

 snake can protrude from the jaws in order to breathe when swallowing large prey, which causes great dis- 

 tension of jaws. (2) Gall bladder. (3) Liver. (4) Heart. (5) Figure on right, the whole digestive tract. 

 The top is entrance to gullet leading from mouth down to stomach, wliich is the largest portion in 

 centre. Lower portions marked E are intestines. The slightly larger part at end of bowels is the 

 cloaca, and vent. Central figure is a Puff Adder laid open, (i) Fang. (3) Lower jaw. (6) Poison 

 gland. (7) Tongue. (9) Windpipe. (10) The stomach (coloured white) showing gullet leading down 

 from mouth. The black-looking parts on which it rests are masses of yellowish fat. (11) Beginning 

 of the intestines (covered with fat). (12) Heart. (13) Veins and arteries. (14) Lung (coloured 

 black). White streak along it is the windpipe. (15) Windpipe on surface of lung. (16) Liver. 

 (17) and (18) Intestines. These are enveloped in fat. (19) Vent. (If the numbers appear 

 indistinct, use a small magnifying glass.) 



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