DEVELOPMP^NT. ^5 



altlioiigli 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 wiiich 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 tlian 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. 

 ISIany 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 Fart II. 



