b4 New Species of Bairacian Reptiles. 
curious details concerning their organization, development, 
and functions. ‘The science of experimental physiology has 
been more indebted to this than to any other class of animals. 
Frogs, being easily procured, and submitting to torture with- 
out any expression of pain, either by cries or convulsions, 
have always been preferred by physiologists as objects of 
experiment, when the peculiarity of their organization offered 
no barriers to their views. For this purpose their remark- 
live habitually upon them. In order to support this intmense 
estruction, 
their enemies, and each female discharges from six to twelve 
hundred eggs annually s 
exist at the present day some points of their organization in- 
volved in obscurity, and some errors have been perpetuated 
trom author to author. * + 
-In-order to become better acquainted with their habits, and 
watch the progress af their developement, ! have this season 
confined great numbers, of both tadpoles and frogs, in con- 
venient receptacles. 
My observations on the former were interrupted by an ac- 
cident, after an attention of rather more than two months. 
ve however collected a few facts worthy of publication. 
‘specimens were of different species and of various ages ; 
but. observation was more particularly directed to the larve 
or tadpole of the Rana pipiens, Linn. as being larger than any 
others inhabiting this state. 
Though not full grown, about the latter end of May they 
generally measured in total length four inches five tenths: 
