122 Mr. J. Hogg on some Amphibians. 



I will now make a few remarks on the Axolotl of Mexico — 

 named by Cuvier Axolotus Mexicanus, and by myself Siredon 

 pisciformis ( 1 838) . 



Dr. Gray, in bis very useful ' Catalogue of the Specimens of 

 Amphibia in the British Museum/ part 2, printed in 1850 

 (wherein he has done my labours justice), places this remarkable 

 Amphibian in his suborder II. Gradientia, and family III. Ple- 

 thodontida; and he says at p. 49, that it "has only been observed 

 in its larva state." He also there cites this passage from Baird 

 (Journ. A. N. S. Phil. 1849, p. 292) :— "It {Siredon) so much 

 resembles the larva of Ambystuma punctata in both external form 

 and internal structure, that I cannot but believe it to be the 

 larva of some gigantic species of this genus. It differs from all 

 known Perennibranchiates (the Aliment ihranchians, mihi) in 

 possessing the larval character of the gular or opercular Hap, 

 this being unattached to the subjacent integuments, and free to 

 the extremity of the chin. The non-discovery of the adult is 

 no argument against its existence." 



Also Charles Bonaparte, Prince of Musignano, in the same 

 year (1850), in his Classification of the Amphibia, considered the 

 Siredon as the mere tadpole of a Salamandra or Batrachian. 



Although Dr. Gray, with his usual accuracy, has referred to 

 " Home, Phil. Trans. 1824," yet he seems not to have fully 

 examined that memoir, and to have overlooked the following 

 passage which I wrote in 1838 respecting it : — 



" Latreille places the Axolotl (Siredon pisciformis) amongst 

 the Caducibranchious Amphibia; but it had been previously 

 discovered that its branchi(e are persistent ; the details of which 

 may be learnt from a paper by Sir Everard Home, published in 

 the 'Philosophical Transactions' for the year 1824, p. 419. 

 One of the accompanying plates accurately represents the ex- 

 ternal gills as still remaining on a female Axolotl when in the 

 state of possessing fully developed ovaria, and just before the 

 ova are shed ; thereby proving her to be a perfect animal. Con- 

 sequently Latreille should have stationed the Axolotl next to 

 the Proteus in his second order." This fact has been fully con- 

 firmed ; and the permanency of the external gills throughout 

 the life of the animal is now well determined. It is frequent in 

 the lake near the city of Mexico ; and the common people con- 

 sidering it ajisli (as indeed some naturalists are inclined to do), 

 sell it as such; and, as Hernandez says, " salubre et gratum 

 praebet alimentum." There seem to me to be three or four 

 species which are not yet correctly known or distinguished. 



M. Dumeril has very recently given an account of the hatch- 

 ing of the young from the ova of the Mexican species (Siredon 

 pisciformis) in the menagerie of the Museum of Natural History 



