Volione XI. October, iSgS- Number 2. 



JOURNAL 



OF 



MORPHOLOGY. 



ON THE MORPHOLOGY AND PHYSIOLOGY OF 

 THE ECHINODERM SPERMATOZOON. 



GEORGE WILTON FIELD, 

 Associate Professor of Cellular Biology in Brown University, Providence, R. I. 



The present work, begun at Naples, October 4, 1892, was 

 carried on there until March 10, 1893. It was continued at 

 the Zoologisches Institut of the University of Munich during 

 the following summer, and brought to a close at the Marine 

 Biological Laboratory, Woods Holl, Mass., during the summer 

 of 1894. 



At the Naples Zoological Station I occupied the " Smith- 

 sonian Table," and my heartiest acknowledgments are due to 

 that institution, and to Professor Dohrn and his corps of 

 assistants at Naples ; also to Professor Dr. Richard Hert- 

 wig at Munich and to Professor Whitman, Director of the 

 Marine Biological Laboratory, who have extended to me the 

 privileges of their laboratories. 



The adaptability of the cells of echinoderms to cytological 

 studies is practically limited to the ovum ; nearly all the other 

 cells are remarkable for their small size, and although even 



