AMBLYSTOMATINAE I I 3 



to pair, and laid eggs which within six months developed 

 into full -sized Axolotls. This certainly looked as if these 

 creatures were not larvae, but a true Perennibranchiate species. 

 But to the general surprise several of these young Axolotls 

 gradually lost their gills, the clefts closed up, the fins of the 

 back and tail disappeared, the head became broader, the crea- 

 tures left the water permanently, and in fact turned into the 

 already well-known terrestrial Atnblystoma tigrinum. The other 

 brothers and sisters of the same brood remained aquatic Axolotls, 

 which thereby revealed themselves after all as the larval and not 

 as the perfect stage of this remarkable species. 



At the suggestion of Kolliker and Weismann, Frl. Marie 

 von Chauvin * undertook, at the University of Freiburg, long and 

 carefully conducted experiments, showing (1) that little Axolotls 

 can comparatively easily be caused to develop further into the 

 perfect Amllystoma if they are induced to breathe air more 

 frequently than usual ; shallow vessels, perhaps also insufficiently 

 aerated water, will produce the desired result ; (2) that the 

 commencing metamorphosis can again be checked, the shrinking 

 gills then undergoing fresh development ; (3) that they can 

 be forced to remain Axolotls ; (4) that the cutting off of the 

 gills has no influence upon their possible metamorphosis, the 

 gills being easily and quickly renewed. The same lady found 

 also that Amllystoma, the perfect form, lives in the water 

 during the pairing time and behaves in the same way as the 

 Axolotls. 



The latest observations have been made by Metzdorff. 2 Axo- 

 lotls, at least those which are kept in captivity in Europe, are 

 ready for propagation several times in the year, either in the 

 spring, from April to June, or in December. The male deposits 

 spermatophores, which in the following night are taken up by 

 the female into the cloaca. On the following day, preferably in 

 the afternoon, she grasps a suitable leaf, for instance that of 

 Vallisneria, with the hind-limbs, and presses it against the vent. 

 The eggs are expelled by strong wriggling movements of the 

 body, and are formed into three or four packets of six to ten 

 eggs each, so that about thirty eggs are laid at one sitting. 



1 Zeitschr. wiss. ZooL xxvii. 1877, p. 522 ; xli. 1891, p. 365 ; Zool. Anz. 

 1882, p. 513. 



' 2 Zoolog. Garten. 1896, p. 114. 



VOL. VIII I 



