THE GERM-CELLS OF CICADA (TIBICEN) 

 SEPTEMDECIM (HOMOPTERA). 1 



ELMER L. SHAFFER, 

 DEPARTMENT OF BIOLOGY, PRINCETON UNIVERSITY. 



CONTENTS. 



A. Introduction 405 



B. Materials and Methods 406 



C. Observations on Chromosomes AO7 



1. Diploid chromosome groups 407 



(a) Spermatogonia 407 



(b) Follicle-cells 408 



(c) Embryonic cells 410 



(d) Somatic cells 410 



2. Spermatocytes 411 



(a) Growth stages 411 



(b) Maturation tetrads 412 



(c) Maturation Divisions 413 



(d) Giant spermatocytes 414 



3. Growth Stages and Synapsis in Oocyte 415 



4. Chromatin Nucleoli in Oocyte 417 



5. Discussion of Chromosomes 419 



(a) Review 419 



(b) Ring Tetrads 421 



(c) Synapsis 422 



D. Observations on Mitochondria 423 



1. Mitochondria in Spermatogenesis 423 



(a) Spermatogonia 423 



(b) Spermatocytes 425 



(c) Transformation of Spermatid 427 



(d) Discussion 427 



2. Nutrition of Egg 429 



3. Mitochondria in Oogenesis 433 



(a) Mitochondria in growth stages 433 



(b) Yolk formation 435 



(c) Discussion 438 



4. Significance of Perinuclear Zone 441 



(a) Relation to yolk-nuclei 441 



(b) Origin of Mitochondria 443 



E. General Considerations 446 



1. Chromosomes 446 



2. Mitochondria 448 



F. Summary 450 



1 A thesis presented to the Faculty of Princeton University, in candidacy for the 

 degree of Doctor of Philosophy. 



404 



