FORMATION OF NOTOCHORD IN AMPHIBIA. 299 



are added to the notochord, the rest, as far as I have been able 

 to determine, remain as part of the permanent dorsal wall of the 

 archenteron. I have never seen a section of an embryo that 

 would warrant my stating that some of these cells become added 

 to the mesoderrn, although in the posterior region of the embryo 

 endoderm and mesoderrn are connected for a much longer time 

 than they are in the embryo of Bufo. 



LITERATURE. 



1. Balfour, F. M. 



'80 Comparative Embryology. Vol. II. The Macmillan Company, New York, 

 1880. 



2. Bracket, A. 



'02 Recherces sur 1'ontogenese des Amphibians, Urodeles et Anoures. Archiv. 

 de Biologic. T. XIX., 1902. 



3. Brauer, A. 



'97 Beitrage zur Kenntniss der Entwicklungsgeschichte und der Anatomic der 

 Gymnophionen. Zool. Jahrbiich, Bd. X., 1897. 



4. Eycleshymer, A. C. 



'95 The Early Development of Amblystoma, with Observations on Some Other 

 Vertebrates. Journ. Morph., Vol. X., 1895. 



5. Field, H. H. 



'95 Bemerkungen iiber die Entwicklung der Wirbelsaule bei den Amphibien ; 

 nebst Schilderung eines abnormen Wirbelsegmentes. Morph. Jahrbiich, Bd. 

 XXII., 1895. 



6. Goette, A. 



'75 Die Entwickelungsgeschichte der Unke. Leipzig, 1875. 



7. Hertwig, 0. 



'81 Die Entwicklung des mittleren Keimblattes der Wirbelthiere, I. Jena, 1881. 



8. Hertwig, 0. 



'83 Die Entwicklung des mittleren Keimblattes der Wirbelthiere, II. Jena, 1883. 



9. Houssay, F. 



'90 Etudes d'embryologie sur les vertebres. Archiv. de Zool. Exper. et Gener., 

 T. VIII., 1890. 



10. Jordan, E. 0. 



'93 The Habits and Development of the Newt. Journ. Morph., Vol. VIII., 1893. 



11. King, H. D. 



'01 The Maturation and Fertilization of the Egg of Bufo lentiginosus. Journ. 

 Morph., Vol. XVII., 1901. 



12. King, H. D. 



'02 The Gastrulation of the Egg of Bufo lentiginosus. American Naturalist, Vol. 

 XXXVI. , 1902. 



13. Lwoff, B. 



'94 Die Bildung der primaren Keimblatter und die Entstehung der Chorda und 

 des Mesoderms bei den Wirbelthieren. Bull, de la Soc. Imp. des Nat. de 

 Moscou, Bd. VIII., 1894. 



