524 



BIOLOGY OF THE PROTOZOA 



and of the homogeneous chromatin mass of Arioplophrya bran- 

 chiaruiii, the granules of chromatin collecting in the center of the first 

 maturation spindle. In Didinium, Chilodon and Anoplophrya 

 these granules fuse until a definite number of chromosomes result— 



/ 





Fig. 217. — Chilodon uncinatus. Third division and interchange of nuclei of diploid 

 {A) and tetraploid {B) stock. (After MacDougall.) 



16 in Didinium, 4 in Chilodon (8 in the tetraploid form found by 

 MacDougall, 1925), and (3 in Anoplojjhrya In Uroleptvs a similar 

 fusion of granules results in 8 chromosomes (Fig. 36, p. 78). 

 Kofoid and Swezy (1919) described the lateral fusion and reduction 

 in number of chromosomes from 52 to 26 in the vegetative division 



