700 REPTILIA — BOA CONSTRICTOR. 



into several brighter colors, pale yellow, or vivid crimson, vi^hich form spots 

 of the size of half one's finger ; some of these descend from the spine half 

 way down the back ; and others appear on the sides, arms, and tail. Some- 

 times the animal becomes all over spotted with brown spots, of a greenish 

 cast. When it is wrapped up in a white linen cloth for two or three 

 minutes, the natural color becomes much lighter, but not quite white, as 

 some authors have pretended; however, it must not hence be concluded 

 that the chameleon assumes the color of the objects which it approaches ; 

 this is entirely an error, and probably has taken its rise from the continual 

 changes it appears to undergo. 



When the chameleon changes place, and attempts to descend from an 

 eminence, it moves with the utmost precaution, advancing one leg very 

 deliberately before the other, still securing itself by holding whatever it can 

 grasp by the tail. It seldom opens the mouth, except for fresh airj and, 

 when that is supplied, discovers its satisfaction by its motions, and the fre- 

 quent changes of its color. The tongue is sometimes darted out after its prey, 

 which are flies ; and this is as long as the whole body. The eyes are re- 

 markably little, though they stand out of the head ; but the most extraordi- 

 nary part of their conformation is, that the animal often moves one eye, 

 when the other is entirely at rest; nay, sometimes one eye will seem to look 

 directly forward, while the other looks backward ; and one will look upwards, 

 while the other regards the earth. 



ORDER III. — OPHI DI A. 



The ophidia, or serpents, have a heart with two auricles ; body much elon- 

 gated, cylindrical, destitute of feet, generally covered with scales. 



THE BOA CONSTRICTOR.' 



The ground color of the body of the great boa, which is the largest and 

 strongest of the serpent race, is yellowish gray, on Avhich is distributed, 

 along the back, a series of large, chain-like, reddish brown, and sometimes 

 perfectly red variations, with other small and more irregular marks and 

 spots. 



The great boa is frequently from twenty-five to thirty feet in length, and 

 of a proportionate thickness. The rapacity of these creatures is often their 

 own destruction ; for whenever they seize and swalloAv their prey, they 

 seem like surfeited gluttons, unwieldy, stupid, helpless, and sleepy. They 

 at the same time seek for some retreat, where they may lurk for several 



' The ffenus Boa has the anus with a hook on each side; body compressed, thickest in 

 the middle; tail prehensile; scales small, at least upon the posterior part of the head. 



