FOOD AND GROWTH 55 



The uniform growth distinctive of reptiles may apparently 

 cease only with the extinction of life ; and for this reason it 

 seems unwise to discredit the stories of unusually gigantic 

 crocodiles, pythons, and anacondas which are from time to 

 time reported, although in some cases these are doubtless 

 exaggerated. 



An idea is prevalent that the growth of reptiles is exceed- 

 ingly slow, and this is doubtless true in many cases. For in- 

 stance, the young of the scheltopusik, or glass-snake, are stated 

 to be many years in coming to maturity. It is also practically 

 certain that the giant land-tortoises of the Mascarene and Gala- 

 pagos Islands take an immense time before reaching their full 

 size. Again, the American painted terrapin is known, from 

 the result of observation, to be very slow in its growth. A 

 specimen, for instance, in which in its second year the shell 

 measured 26*5 millimetres in length, took twenty-five years be- 

 fore it attained a full average shell-length, that is to say 121 

 millimetres ; and it is inferred that an example in which the 

 shell measured 163 millimetres was much older. That the rate 

 of growth of the first specimen was normal, is demonstrated by 

 the circumstances that for many years it progressed pari passu 

 with that of a number of other examples kept under observa- 

 tion. These showed that during the first half-dozen years the 

 rate of increase is so regular that specimens can be arranged in 

 series corresponding to their age from their similarity in size. Up 

 to this period the age of specimens is indicated by the number 

 of lines of growth on the horny shields covering the shell ; but 

 after the seventh year these shields tend to become smooth so 

 that the annual lines of growth become more or less obliterated, 

 when the possibility of reckoning the age by this means be- 

 comes proportionately difficult. 



On the other hand, statements as to the slowness of growth 

 of the American alligator {Alligator mississippiensis) are not 

 supported by observations on specimens in the New York 

 Zoological Park. It was stated, for instance, by an American 

 writer that : " Alligators grow very slowly. At fifteen years 

 of age they are only two feet long. A twelve-footer may be 

 reasonably supposed to be seventy-five years of age." 



The observations at the New York Zoological Park showed 

 that young alligators when first hatched measured eight inches 



