302 PHILOSOPHY OF ZOOLOGY. 



have been proper to have made upon it, or upon animals 

 which resemble it, experiments similar to those we have 

 made on the proteus. If, in his researches with regard to 

 ambiguous reptiles, he had not contented himself with exa- 

 mining only their skeletons, but had examined also the 

 larva of the salamander, while yet alive, we are certain that 

 his investigations would have conducted him to opinions en* 

 tirely opposite to those which he has been led to form. 



" In our investigations on this point, we have directed our 

 attention to the above mentioned larvae, to observe particu- 

 larly the changes which occur in their intimate structure, 

 when they are transformed into perfect animals. Between 

 the siren and these larvae there is the greatest resemblance, 

 not only in regard to the structure of the branchial arches, 

 but also to the nostrils ; for, in the siren, as well as in these 

 larvae, the nostrils do not open into the mouth. This cir- 

 cumstance prompted us to examine the condition of the 

 bones of the face in these larvae, and we have thereby sa- 

 tisfied ourselves, that the larvae of the salamander is unable 

 to breathe by lungs, until the maxillary bones, the zygo- 

 matic arches, and the palatine bones are sufficiently de- 

 veloped to form the canal of the nostrils, in such a manner 

 that its posterior extremity may open into the mouth. Be- 

 fore this canal is so formed, these larvae are unable to respire 

 atmospheric air, and, if taken out of the water, they then 

 soon die ; and, therefore, guided by analogy, we incline to 

 believe, that, to the siren, whose nostrils < ne penetrent point 

 dans la bouche,' the same things ought to happen. More- 

 over, as its lungs are similar in all respects to those of the 

 salamander, and are furnished with a true glottis, we are 

 farther of opinion, that the siren is the larva of some rep- 

 tile, the genus of which is as yet unknown, and which will 

 differ from its larva in not possessing gills, and in having a 

 trunk somewhat longer. 



