CONTENTS. 
INTRODUCTION. 
A. Organization of the Egg 
А В. Ascidian Embryology 
C. Methods and Material 
I. THE Ovarian Eco. 
1. Development of the Ovocyte 
2. Test Cells and Chorion . 4 
3. Structure of Fully Formed Озу 
II. MATURATION AND FERTILIZATION. 
A. Maturation 
. Disappearance of N кома Membrane 
. Chomosomes ; 
. Nucleolus 
. Spindle Formation 
. Movements of Spindle d Мәде Pinas; Formate of Polar Bodies 
B. Fertilisation - 5 
1. Entrance of Hai 
2. Movements of Oöplasm 
x a. Localization of Yellow Proioplsani 
b. Localization of Clear Protoplasm and Yolk 
3. Development of Sperm Nucleus and Aster 
4. Path of Spermatozoon within the Egg 
5: The Egg Nucleus and its Movements 
6. Sperm e and First basics Spindle 
7. Dispermy 
ыла ` 
ПІ. ORIENTATION оғ EGG AND EMBRYO. 
1. Van Beneden and Julin’s deinen of Orientation 
2, Seeliger's System 
8. Samassa's System 
4. Castle's System . ; 
5. Evidences in Favor of Van Бач end J ulin’ s Ted 
IV. CELL-LINEAGE. 
A. Nomenclature ; 
В. Cleavage of the Egg ; First to Heventh бештей. of Cells 
. First Cleavage; 1-2 Cells 
. Second Cleavage; 2-4 Cells 
. Third Cleavage; 4-8 Cells 
. Fourth Cleavage; 8-16 Cells 
. Fifth Cleavage; 16.32 Cells 
. Sixth Cleavage ; 32-64 Cells i 
C. Сабоа; Seventh to Ninth Generalia of Cells ; 
7. Seventh Cleavage; 64-76 Cells, 76-112 Cells . : i s 
8. Eighth Cleavage; 112-132 Cells, 132-218 Cells . . : 4 
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