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NOTES ON THE LIFE HISTORY OF THE AXOLOTL, 



BY 



REV. ANDREW JOHNSON, M.A., F.L.S., 

 2SM APRIL, 1883. 



I HAVE the honour to-night to bring before the notice of the 

 Society Hving specimens of what are commonly called Axolotl, 

 which have been reared from the egg at Blackheath. I may, 

 perhaps, be allowed to explain to some of the members present 

 why these uncouth looking little reptiles have a special interest 

 for naturalists. It is, of course, well known that the Division 

 of Reptilia, which is called Batrachian (to which the frog, 

 newt, and salamander belong), pass the first portion of their 

 existence in the water, breathing by means of branchiae, that 

 is, certain appendages corresponding to the gills of fishes, 

 but placed outside the body ; the blood circulates through 

 the ramifications of these organs, and returns to the system 

 oxidized and purified by contact with the air contained in 

 the water which has played over them. After a time these 

 gills or branchiae diminish in size, and finally disappear ; the 

 animal changes in form, loses its tail, if it belongs to the 

 sub-division Anoura, or retains it if it is one of the Urodela, 

 i.e., a Salamander or a Triton ; and comes to the surface to 

 breathe by means of the lungs. Animals which thus eventually 

 lose their branchiae are called Caducibranchiate. But there 

 are one or two genera which appear not to get beyond the 

 imperfect or larval condition, and as far as is known, retain 

 their gills all their lives. Such is the Proteus, and such was 

 long thought to be the case with the Siredon Mexicanum or 

 Pisceforme (so-called). Cuvier was the first to call in 

 question the right of the last-named animal to the position 

 assigned to it, as he felt convinced from its analogy in all 



