208 TIMEHRI. 
by the waterside, the boas are able to secure all that they 
need, and they certainly make good use of their oppor- 
tunities, for when caught, they are always well-nourished 
and fat. Rodents and birds seem to be favourite articles 
of diet, not only with this species, but with the generality, 
if not all, of the constricting snakes. 
The part which these and kindred reptiles play in 
maintaining the balance of nature in a group of such 
remarkable fecundity as the rodents, must be therefore 
of considerable importance to man in the tropics, the 
more so that the greater number of rodents are among 
the most serious depredators on cultivation in general. 
It must be stated, however, that the range of food of 
the boas includes a great variety of other animals, such 
as the great Salempenta or Teguexin lizards, and the 
alligators, besides the smaller mammals generally, and 
even the small wood-deer and the peccary. The securing 
of prey such as the mammals or birds, is ordinarily an 
operation of short duration, since the highly organised 
animal being once enwrapped, succumbs rapidly under 
the enormous pressure of the folds about its body. It is 
not often, therefore, that an observer comes upon the field 
during the process, except when poultry bas been seized 
close to a dwelling, and their cries have attraéted the atten- 
tion of the inmates. 
_In the case of the alligators it is far otherwise, and 
the process is always a long one, taking on the charaéter 
of a combat except where the snake is disproportionately 
large. In one case observed, the contest certainly ex- 
tended over two days; and it would seem that, if the 
snake once succeeds in infolding the alligator in its coils 
in an advantageous position, the latter must succumb, 
