SUPPLEMENT. 413 



much larger and more distant, and the color brown instead of 

 black. 



This animal is probably amphibious, although it has not the 

 flat tail of the Pelamides ; nor did the examination of its ex- 

 terior enable us to discover any thing in its structure, pecu- 

 liarly adapting it to a residence in the water, excepting only 

 the remarkable facility of bending in a vertical direction. This 

 motion, which may be observed in the leech, and various other 

 aquatic animals, is quite as important as a horizontal one to an 

 inhabitant of the ocean, and comparatively useless in an animal 

 confined to the land. 



Internal Structure. The structure of the spine in this 

 animal is very singular, and different from that of any serpent 

 which we have seen, or known to be described. Its course 

 throughout the greater part of the body is regularly undulating 

 or flexuous, consisting of successive curves upward and down- 

 ward. The structure of the different vertebras varies to ac- 

 commodate itself to this configuration, so that the spine cannot 

 be extended into a straight line without dislocation of its parts. 

 In the portion of spinal column which we examined, each 

 curve consisted of about nine vertebras. Each vertebra was 

 articulated by a round head on its posterior extremity to a 

 socket in the anterior extremity of the next.* It had five 

 principal processes, one a spinous process ; two anterior, and 

 two posterior transverse processes. There were also smaller pro- 

 cesses articulated with the ribs, and a sharp longitudinal prom- 

 inence underneath. The spinous processes varied remarkably 

 in shape and size, according to the part of the spine in which 

 they were situated. Those occupying the top of the curve 

 were very broad, and those of the bottom of the curve very 

 narrow, the latter being not more than half the breadth of the 



■^ This is the reverse of what Cuvier asserts of serpents in general, in his learned work 

 on comparative anatomy. He states that the tubercle is on the anterior, and the cavity on 

 the posterior part of the vertebra. " La partie anterieure du corps de la vertebre pr^sento 

 un tubercule arrondi demi-spherique ; et la partie posterieure offre, an contraire, une cavite 

 correspondante ; de sorte que chacune des vertebres est articulee en genou avec celle qui 

 la suit, et avec celle qui la precede." — Le goiis d'ariatomie comparee. I. 176. — We are in- 

 duced to believe that in the above passage the terms anterior and posterior must have been 

 misplaced. The tubercle, we think, always occupies the posterior part of the vertebra. 



