86 SYNGAMY IN PR(3T0Z0A 



Hartmann (1909) gave a general account of autogamy amongst Pro- 

 tista, but a perusal of his paper shows that most, if not all, of the alleged 

 instances are based on very slender evidence. 



PEDOGAMY.— There is another type of self-fertilization which differs 

 from true autogamy in that a single individual first divides into two 

 daughter forms after division of its nucleus. When the nucleus of each 

 has undergone maturation or reduction divisions, the two daughter cells 

 which are gametes unite. The process which is known as jjedogarny has 





W 



^^, 



.-^^^..^.^ 





F 



Fig. 49. — Pedogamy in Actinosphceriuni eicMomi ( x 80). (From Lang, 1901, 

 AFTER Richard Hertwig, 1898.) 



A. A single multinucleated individual in a primary cyst. 



B. Division into a number of uninucleated individuals which become enclosed in secondary cysts. 

 (!. The contents of each secondary cyst divide into two. 



D. The division completed, after which each nucleus undergoes two reduction divisions. 



E. The two gametes in each secondary cyst imite. 



F. Secondary cysts containing zygotes resulting from the union of the gametes. 



been studied by Richard Hertwig (1898) and others in the multinucleated 

 Heliozoon Actinosphcerium eichkorni (Fig. 49). An individual encysts 

 and divides into a number of uninucleate forms, which become enclosed 

 in secondary cysts. Within each secondary cyst a further division into 

 two individuals takes place. The nucleus of each of these undergoes 

 two reducing divisions, after which union takes place. In this case the. 



