118 GYMNOPHIONA. 



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

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

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

 teeth, and lower jaw. 



Madame von (Jhauvin 1 was able, by gradually accustoming Axolotl 

 larva; to breathe, artificially to cause them to undergo the above meta- 

 morphosis. 



It seems very possible, as suggested by Weismann 2 , that the existing 

 Axolotls are really descendants of Arnblystoma forms, which have reverted 

 to a lower stage. In favour of this possibility a very interesting discovery 

 of Filippi's 3 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 tamiatus have been 

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

 might be possible artificially to cau&e the Newt to revert to a perenrn- 

 branchiate condition. 



Gymnophiona. The development of the Gymuophiona is almost 

 unknown, but 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 Ccecilia oxyura. In Ccecilia compressicauda, Peters (No. 108) 

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

 larvae within the uterus two elongated vesicular gills. 



BIBLIOGRAPHY. 

 Amphibia. 



(93) Oh. van Bambeke. "Kecherckes sur le developpement du Pelobate brun." 

 Memoires couronnes, etc. dc I'Acad. roy. de Btlyique, 1868. 



(94) Ch. van Bambeke. " Keenerches sur 1'enibryologie des Batraciens." 

 Bulletin de I'Acad. roy. de Belgique, 1875. 



(95) Ch. van Bambeke. "Nouvelles recherches sur 1'embryologie des Batra- 

 ciens." Archives de Biologie, Vol. i. 1880. 



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

 Archiv, 1834. 



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

 Anzeif/er, 1880. 



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

 Studies from the Biological Laboratory of the Joints Hopkins University, No. ir. 1880. 



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

 Miiller's Archiv, 1848. 



(too) A. Ecker. Icones Physiolog. 1851 1859. 



(101) A. Gotte. Die Entivicklungsgesehichte der Unke. Leipzig, 1875. 



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

 18731879. 



(103) T. H. Huxley. Article "Amphibia" in the Encyclopedia Britanniea. 



(104) A. Moquin-Tandoii. "Developpement des Batraciens anures." Annales 

 des Sciences Naturelles, in. 1875. 



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



2 Zeit.f. wiss. Zool., Bd. xxv., sup. 1875. 



3 Archivio per la Zooloyia, I' Anatomia e la Fisiologla, Vol. i. Genoa, 1861. Conf. 

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

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



