THE MATURATION AND FERTILIZATION OF 

 THE EGG OF LIMAX AGRESTIS (LINNE). 



ESTHER FUSSELL BYRNES. 



TABLE OF CONTENTS. p^^^ 



Introduction 201 



I. Maturation of the Egg 202 



1. The Archiamphiaster , 202 



2. Ovarian Eggs 204 



3. First Maturation Spindle. Extrusion of the First Polar Body .... 206 



4. Formation of the Second Maturation Spindle. Extrusion of the 



Second Polar Body 207 



II. Structure and Maturation of the Spermatozoon 211 



1. Structure of the Spermatozoon '. 211 



2. Fertilization 212 



III. Observations on Abnormal Ova 218 



1. Polyspermy 218 



2. Abnormalities Other than Polyspermy 219 



IV. Formation of the Spindle 220 



V. Structure of the Cytoplasm. Archoplasm 222 



VI. The Centrosome 226 



VII. Summary 227 



VIII. Appendix 228 



Material. Collecting and Keeping 228 



Preparation of Material 229 



Introduction. 



The study of the maturation and fertilization of the egg of 

 Limax agrestis was carried on in the Biological Laboratory of 

 Bryn Mawr College, under the direction of Prof. T. H. Mor- 

 gan. I gladly take this opportunity of thanking Professor 

 Morgan for his kind interest and helpful guidance during the 

 course of the work. 



The development of the egg of Limax agrestis was first 

 studied by Warneck in 1850; and in 1881 Mark published his 



