54 TEXT-BOOK OF EMBRYOLOGY. 



small enough not to allow the eggs to slip past one another. In this way the stages may be 

 kept in order, and the tightly- corked tubes may be handled in any way to get the best light 

 on the eggs. 



References for Further Study. 



ASSHETON, R.: The Segmentation of the Ovum of the Sheep, with Observations on the 

 Hypothesis of a Hypoblastic Origin for the Trophoblast. Quart, Jour, of Mic. Science, 

 Vol. XLI, 1898. 



BLOUNT, M.: The Early Development of the Pigeon's Egg, with Especial Reference to 

 the Supernumerary Sperm Nuclei, the Periblast and the Germ Wall. Biolog. Bull., Vol. 

 XIII, No. 5, 1907. 



CONKLIN, E. G.: Karyokinesis and Cytokinesis. Jour. Acad. Nat. Sci. 0} Philadelphia, 

 Vol. XII, 1902. 



CONKLIN, E. G.: The Embryology of Crepidula. Jour, of MorphoL, Vol. XIII, 1897. 



EYCLESHYMER, A. C.: The Early Development of Amblystoma, with Observations on 

 Some Other Vertebrates. Jour, of MorphoL, Vol. X, 1895. 



HARPER, E. H.: The Fertilization and Early Development of the Pigeon's Egg. Am. 

 Jour, of Anal., Vol. Ill, No. 4, 1904. 



HATSCHEK, B.: Studien iiber Entwickelung des Amphioxus. Arbeiten aus dem zool. 

 Instil, zu Wien, Bd. IV, 1881. 



HERTWIG, R.: Eireife, Befruchtung u. Furchungsprozess. In Hertwig's Handbuch d. 

 vergleich u. experiment. Entwickelungslehre der Wirbeltiere, Bd. I, Teil I, 1903. 



LILLIE, F. R.: The Development of the Chick. New York, 1908. 



MORGAN, T. H.: The Development of the Frog's Egg. New York, 1897. 



SOBOTTA, J.: Die Befruchtung u. Furchung des Eies der Maus. Arch. f. mik. Anat., 

 Bd. XLV, 1895. 



VAN BENEDEN, E.: Recherches sur les premiers stades du developpement du Murin 

 (Vespertilio murinus). Anat. Anz., Bd. XVI, 1899. 



WILSON, E. B.: The Cell in Development and Inheritance. 2d Ed., 1900. 



