



Mara Lib, ^ BIOLOGY 



ZOOLOGY DEPIj UB * AR 



Reprinted from DENISON UNIVERSITY BULLETIN, JOURNAL OP THE SCIENTIFIC LABORATORIES, 

 Vol. XIX, September, 1921 



THE CYTOLOGY OF THE SEA-SIDE EARWIG, 

 ANISOLABIS MARITIMA BON. 



PART I 



SIDNEY I. KORNHAUSER 



From the Zoological Laboratory of Denison University, and the Biological Labo- 

 ratory of the Brooklyn Institute of Arts and Sciences at Cold Spring 

 Harbor, Long Island 



WITH THREE PLATES 



CONTENTS 



1. Introduction 234 



2. Historical Review 235 



3. Methods 236 



4. The Gonads 237 



5. The Diploid Chromosomes 238 



6. The Spermatocyte Chromosomes 240 



7. Discussion 244 



8. Summary 245 



9. Bibliography : 246 



10. Explanation of Plates 246 



1. INTRODUCTION 



The forficulid, Anisolabis maritima Bon., which is found under 

 the stones and riff-raff at the high-tide mark, is especially beauti- 

 ful material for cytological study. The chromosomes are clear 

 and distinct; the cytoplasmic structure, nicely demonstrable; 

 and good preservation is not difficult. The differentiation of the 

 oocyte and nurse cell and their subsequent growth present many 

 interesting problems which will be taken up in another paper. 

 The origin and distribution of mitochondria in both the sex 

 and the embryonic cells may also be studied profitably in this 

 species. For the present, the author has confined himself chiefly 

 to the chromosome number, and the origin and fate of the sex- 

 chromosomes in the male. The work was begun in the summer 



234 



