THE GERM CELLS IN ASCARIS INCURVA 



H. B. GOODRICH 



Union College, Schenectady, New York 



ELEVEN TEXT FIGURES AND THREE PLATES 



CONTENTS 



I. Introduction 61 



II. Material and technique 62 



III. Observations on chromosomes 63 



A. Spermatogenesis 63 



1. Spermatogonia 63 



2. Pre-synaptic and synaptic stages 64 



3. Post-synaptic stages 64 



4. The prophases 65 



5. The maturation divisions 66 



B. Oogensis 67 



1. Oogonia 67 



2. Growth stages and prophases 68 



3. The maturation divisions 69 



IV. Discussion 70 



A. The sex chromosome complex 70 



B. The X-chromatin and the plasmasome 73 



C. The Seriation 74 



D. The pro-chromosomes and synapsis 77 



V. The mechanism of the unequal mitosis 79 



A. Description 79 



B. Discussion 82 



VI. Size dimorphism of spermatozoa 83 



VII. The early cleavage 86 



VIII. Summary and conclusion 89 



IX. Bibliography 91 



INTRODUCTION 



This paper presents a study of the development of the germ 

 cells in Ascaris incurva. In a preliminary note (Goodrich 

 '14) I reported the existence in this nematode of a remarkable 

 sex-chromosome complex consisting of eight X-chromosomes 



61 



