Volume- XV. February, iSgg. Number 3. 



JOURNAL 



MORPHOLOGY. 



STUDIES ON THE MATURATION, FERTILIZA- 

 TION, AND CLEAVAGE OF THALASSEMA 

 AND ZIRPHAEA.i 



BRADNEY B. GRIFFIN. 



CONTENTS. p^gg 



Introduction 584 



Part I. Thalassema 587 



I. The Ovarian Egg and Nucleolus 587 



II. Achromatic Structures 589 



a. The First Polar Division 589 



b. The Second Polar Division 596 



c. The Sperm-Amphiaster 597 



d. The Cleavage-Amphiaster 599 



III. The Chromatin 603 



a. In Maturation 603 



b. In Fertilization and Cleavage 612 



IV. The Polar Bodies 613 



Part II. Zirphaea 616 



V. Development of Ova.. _ 616 



VI. The Centrosome 618 



VII. The Chromatin 620 



a. In Maturation 620 



b. In Cleavage 623 



Part III. Summary and Conclusion 624 



1 The death of Mr. Griffin, in April, 1898, occurred before the final revision of 

 the manuscript of the following paper, which had been placed in my hands as a 



