134 SNAKES. 



elastic membranes, so that the windpipe is capable of 

 being extended like an india-rubber tube, and of regaining 

 its former position. 



The length of it naturally varies according to the size 

 and species of serpent ; but as a rule it is always 

 much longer comparatively than in man. In a full-sized 

 rattlesnake, the trachea is about tw^enty inches long. In 

 a boa constrictor, also, though a much larger snake, it 

 measures about the same. In smaller snakes it is, of 

 course, much shorter ; but there is the same singular 

 diversity in this as we find in other serpent anomalies, 

 viz. a great variation in the length in snakes of equal 

 size, and without any very apparent reason. 



Bingley, in his Animal Biography^ 1820, describes the 

 appearance of a large snake (M'Leod's celebrated boa) 

 when gorging a goat ; but the account, like those of that 

 time, is more sensational than scientific. * His cheeks were 

 immensely dilated, and appeared to be bursting, and his 

 wijidpipe projected three inches beyond his jaws.' 



Broderip, a few years later, 1825, more lucidly and dis- 

 passionately describes what he had observed. ' I have 

 uniformly found that the larynx is, during the operation 

 of swallowing, protruded sometimes as much as a quarter 

 of an inch beyond the edge of the dilated lower jaw. I 

 have seen, in company with others, the valves of the glottis 

 open and shut, and the dead rabbit's fur immediately before 

 the aperture stirred, apparently by the serpent's breath, 

 when his jaws and throat were stiff, and stretched to excess ' 

 {^Zoological Journal, \\. 1826). This account is quoted from 

 the paper entitled, ' Some Account of the Mode in which 



