43 
Viscera ,—The only part of the viscera, which the limited openings 
permitted us to examine, were a portion of the lung and oesopha¬ 
gus with the mesentery and blood vessels, also a small part of the 
stomach. The lung was a long cellular and tubular viscus, as 
in other serpents, but with this remarkable peculiarity. It was 
successively dilated and contracted so as to adapt itself to the 
cavities formed by the undulations of the spine. The oesopha¬ 
gus was also unequal, but without relation to the cavities of the 
spine, not being in contact with it. In the stomach was found a 
mass of scales, also the tail and part of the skin of a serpent of' 
a different species, having all the scales carinate. 
In regard to the use or final cause of the curvatures in the 
back-bone, which give so peculiar a character to this animal; it 
*■ is obvious that two important ends are effected by it. These are 
an increase of flexibility and an increase of strength in •vertical mo¬ 
tions, 
1. The flexibility is increased, because in any given length of 
body, there will be more joints in a crooked, than there would be 
in a straight spine, composed of vertebra; of the same di¬ 
mensions. 
2. The strength in vertical motions is increased, since the 
fulcrum formed by the highest articulation is more remote from 
j the power applied by the lateral muscles, and the fulcrum form¬ 
ed by the lowest articulation is also more remote from the pow¬ 
er applied by the dorsal muscles ; than they would be if the spine 
pursued a straight and intermediate course. 
The dorsal muscles, however, being bound down by an apo¬ 
neurosis, so as to pursue nearly the course of the spine, are near¬ 
er their fulcrum and have less of this advantage than the lateral 
muscles, which are farther from their fulcrum ; so that the great¬ 
est power is probably that which is exerted in the forward flex¬ 
ion or extension of the body. This power is the one which would 
be most useful to the animal in swimming at the surface of the 
water with a motion in any degree vertical. 
