222 



GENERAL ZOOLOGY 



(Fig. 137, D, E, and /O . In the case of the V-shaped chromosomes, 

 shown in the illustration, the chromosomes are arranged with the 



Fig. 137. — Diagram of karyokinesis. A, resting stage, two centrosomes in 

 cytoplasm near nucleus; B, early prophase, spireme stage; C, later prophase, 

 spireme segmented into eight chromosomes; D, polar view of chromosomes at 

 metaphase; E, side view of spindle and chromosomes at metaphase, each chromo- 

 some undivided; F, metaphase, each chromosome shows a lengthwise split; 

 G, side view of a single chromosome dividing, early anaphase; H, anaphase; 

 I, telophase; J, two complete daughter cells. 



apices of the V's pointed toward the spindle to which they 

 become attached. 



In the next stage, the anaphase, each chromosome, beginning 

 at the apex of the V, is split longitudinally into halves, the result 

 being the formation of two daughter groups of chromosomes, 



