118 GYMNOFHIONA. 



metamorphosis a pulmonary respiration takes the place of a branchial one, 

 the gills are lost, and the gill-slits close. The tail loses its tin and be- 

 comes rounded, the colour changes, and alterations take place in the gums, 

 teeth, and lower jaw, 



Madame von Chauvin' was able, by gradually accustoming Axolotl 

 larvai to breathe, artificially to cause them to undergo the above meta- 

 morphosis. 



It seems very possible, as suggested by Weismann^, that the existing 

 Axolotls are really descendants of Amblystoma forms, which have reverted 

 to a lower stage. In favour of this possibility a very interesting discover)' 

 of Filippi's^ may be cited. He found in a pond in a marsh near Andermat 

 some examples of Triton alpestris, which, though they had become sexually 

 mature, still retained the external gills and the other larval characters. 

 Similar sexually mature larval forms of Triton tseniatus have been 

 described by Jullien. These discoveries would seem to indicate that it 

 might be possible artificially to cause the Newt to revert to a perenni- 

 brauchiate condition. 



Gymnophiona. The development of the Gymnophiona is almost 

 unknown, biit it is certain that some larval forms are provided with 

 a single gill-cleft, while others have external gills. 



A gill-cleft has been noticed in Epicrium glutinosum (Miiller), 

 and in Coecilia oxynra. In Coecilia compressicauda, Peters (No. io8) 

 was unable to find any trace of a gill-cleft, but he observed in the 

 larvse within the uterus two elongated vesicular gills. 



Bibliography. 



Ampliihia, 



(93) Ch. van Bambeke, " Recherches sur le developpement du Pelobate brun. " 

 Memoires couroiines, etc. de VAcad. roy. de Bfl(jique, 1868. 



(94) Ch. van Bambeke. "Recherches sur I'embryologie des Batraciens." 

 Bulletin de VAcad. roy. de Belgique, 1875. 



(95) Ch. van Bambeke. "Nouvelles recherches sur I'embryolc^ie des Batra- 

 ciens." Archives de Biologic, \ol. 1. 1880. 



(96) K. E. von Baer. "Die Metamorphose des Eies der Batrachier," MuUer's 

 Archiv, 1834. 



(97) B. Benecke. "Ueber die EntwicMung des Erdsalamanders." Zoologischer 

 Anzeiger, 1880. 



(98) S. F. Clarke. "Development of Amblystoma punctatum," Part I., External. 

 Studies from the Biologieal Laboratory of the Johns Hopkins University, No. if. 1880. 



(99) H. Cramer. "Bemerkungen lib. d. Zellenleben in d.Entwick.d. Froscheies." 

 Miiller's Archiv, 1848. 



(ioo| A. Ecker. Icones Physiolo^. 1851 — 1859. 



(loi) A. Gotte. Die Entwicklungsgeschichte der Unhe. Leipzig, 1875. 



(102) C. K. Hoffmann. "Amphibia." Klassen %i. Ordnungen d. Thierreiclis, 

 1873—1879. 



(103) T. H. Huxley. Article "Amphibia" in the Encyclopaedia Britannica. 



(104) A. Moquin-Tandon. "-Developpement des Batraciens anures." Annates 

 des Sciences Naturelles, iii. 1875. 



^ Zeit.f. wiss. Zool., Bd. xxvii., 1876. 



'-^ Zeit.f. wiss. Zool., Bd. xxv., sup. 1875. 



3 Archivio per la Zoologia, V Anatomia e la Fisiologia, Vol. i. Genoa, 1861. Conf. 

 also Von Siebold, "Ueber die geschlechtliche Entwicklung d. Urodelen-Larven." 

 Zeit.f. wiss. Zool., Bd. xxviii,, 1877. 



