and Structure of the Proteus Anguitius . 1 05 
four on each side, and their margins are furnished with small 
points, — in the proteus, there are but three on each side* and 
these are smooth. The arches of the proteus have an osseous 
structure,-— those of the siren and larvse are cartilaginous. 
This difference did not escape M. Cuvier, who, speaking of the 
proteus, says, 66 Pappareil osseux qui porte les branchies, est 
beaucoup plus dur que ne Pavons trouve dans la sirene , et dans 
V axolotl : n and in his anatomical description of the latter ani- 
mal, he farther says, 4 4 Vappareil qui supporte les hr and ties d 
de grands rapports avec celui de la sirene , et je crois que, lors 
de la metamorphose, il en reste une partie pour former Pos 
hyoide de la salamandre Now, if the branchial arches of 
the siren be, as M. Cuvier asserts, entirely cartilaginous, al- 
though the cranium, the lower jaw, and the vertebrae be per- 
fectly ossified ; and if these arches, both in form and number, 
be similar to those of the axolotl, which M. Cuvier himself 
regards as a larva, — may it not be presumed that the former 
animal is a larva also ? If, farther, the branchial arches of the 
proteus, which is a perfect animal, be osseous, and entirely dif- 
ferent from those of the siren and all the larvae hitherto known, 
have we not in these facts the strongest reasons for regarding 
the siren as an imperfect animal, and, therefore, essentially dif- 
ferent from the proteus ? 
With regard, next, to the organs of circulation, there are, in 
the larvae of the frog and salamander, as many arteries given 
* The authors here observe, that they have not themselves had an opportu- 
nity of anatomising the sirena lacertina ; and, therefore, with regard to its inter- 
nal structure, they trust entirely to the descriptions of M. Cuvier, who has writ- 
ten largely upon it. 
It may not be out of place to add, that, in the new arrangement of M. Cu- 
vier, the Proteus anguinus stands in the class Reptiles, — order Batraciens, — 
genus (containing as yet only one species,) Proteus. Besides internal lungs, it 
bears externally, like the larva of the salamander, three gills on each side of the 
neek, which it appears to retain through life. 
The Sirena lacertina occupies the same class and order, and is another genus 
consisting only of one species. It is said, like the proteus, to retain through its 
whole life, three gills on each side the neck, and to possess, at the same time, 
lungs internally. 
In the same class and order is placed the Axolotl of the Mexicans, or Sirena 
pisciformis of Shaw. It belongs to the genus Salamandra, of which it is a spe- 
cies. Some allege that it also always retains its gills. — Vide Le Regne Animal , 
tom. ii. p. 101, — 102. — Transl. 
