Tlie Identification of Intracelhdar Structures. 



101 



some way bearers of " factors of heredity." It is quite evident 

 that iu no cases at present observed do the mitochondria or Golgi 

 elements become distributed between the daughter-cells quite like 

 the chromosomes. 



Explanation of Text-figs. 8-14. 

 Illustrating usual and unusual types of Dictyokinesis and Chondrokinesis. 



Letters. — Gx = Golgi rod dividing by binary fission. MR = mitochondrial 

 ring. SB = spindle bridge. (Other letters as in text-figs. 4-7.) 



Fig. 8. — Late anaphase or telophase. Equatorial plate forming. 



Fig. 9. — Late telophase ; spindle bridge established from remains of old spindle 

 fibres. Combination of chromosomes to form a nearly solid mass ; Golgi rods 

 gathered around the forming archoplasmic sphere. 



Fig. 10. — Nucleus reformed ; appearance of karyosome and plasmosome ; re- 

 constitution of sphere ; Golgi rods beginning to clivide (Gx). 



Fig. 11. — First spermatocyte of Paludina (and also exemplifies second sperma- 

 tocyte of Centrums), showing division of large mitochondria by a constriction 

 in the middle across equatorial plate. 



Fig. 12. — First spermatocyte of Centrums, showing mitochondrial ring, which 

 later divides into two sections shaped like those in previous figure. 



Fig. 13. — Type of dictyokinesis, found especially in segmenting eggs (possibly all 

 eggs), in which the Golgi elements lie inert in the cytoplasm, and are not attached 

 to any part of amphiaster. In later stages during organogeny this type reverts to 

 that in text-figs. 4-10. 



Fig. 14. — Type of dictyokinesis in many vertebrate somatic cells (e.g. thyroid), 

 in which the Golgi apparatus breaks up into irregular granules (G), which keep 

 around the zone of the amphiaster, but do not necessarily adhere to the astral rays. 

 This is possibly a transition form between those in text-figs. 4-10 and 13. In text- 

 fig. 14 the mitochondria are drawn in rings ; the ceU is the telophase of mitosis. 



