DEVELOPMENT. 
95 
although it is generally supposed that they live long, as 
do all other reptiles ; we are equally ignorant whether they 
have a stated period of growth, or what may be its dura- 
tion. It is probable that they grow during the whole term 
of their lives, but my observations induce me to believe 
that this augmentation of volume takes place differently 
in the different periods of life, and that it is subject to the 
same laws which regulate the development of the greatest 
part of other vertebrate animals. The thick and rounded 
forms which distinguish the young serpent, disappear in 
the first months of its existence, and it becomes more 
elongated as it approaches the age of puberty. This term 
is fixed in our climate, according to M. Lenz, at the fourth 
year. It appears that after this period serpents increase 
less rapidly than in their earliest years, and that the de*^* 
velopment of their parts has rather relation to volume 
than to length ; this age is marked by distinct traits, and 
the fulness of form. But before arriving at the close of 
their existence, the dimensions of ordinary serpents are 
sometimes doubled ; the thickness of the parts, the obtuse 
and compact head, and the vigorous form, distinguish very 
aged individuals, that are, however, rarely to be met with. 
Many travellers, and especially those of a more remote 
age, speak of serpents of a monstrous size, which they say 
they have encountered in their travels in intertropical 
countries, and which they state as reaching to forty feet 
and upwards.^ In whichever country these great reptiles 
are found, they apply to them the name of Boa Constric- 
tor, familiar to all, although the true boa constrictor of 
systems yields much in dimensions to other species of the 
Boa and the Python. The numerous researches of modem, 
well-informed, travelling naturalists, have belied many of 
the fables which have been promulgated on the nature of 
these Ophidians. We now know that the most gigantic 
do not surpass twenty to twenty-five feet in total length ; 
that their thickness is not above seven inches in diameter ; 
and that the received notions on the great size of some 
species, only repose on the vague surmises of the natives. 
^ See the article Boa, in Part II. 
