PRESH- WATER ANIMALS. 317 



information, the young are about six inches in length, and 

 full-grown individuals sometimes measure fourteen or fifteen 

 feet. Now, if we can suppose any proportionate ratio of 

 growth between the animals in captivity and those in their 

 native condition, it will appear that an enormous time 

 must be consumed before the adult size can be attained. 

 Specimens received at the Gardens nine inches long, eight 

 or nine years since, have only yet reached a length of about 

 thirty inches ! at which rate it would take forty-five to fifty 

 years to attain maturity ! 



