REPRODUCTION 



209 



are grouped according to the distribution of the three main types of 

 the Protozoa-jNIastigophora, Sarcodina and Infusoria. 



A. Division and Reorganization in Mastigophora.— With very 

 few exceptions division in flagellates is longitudinal, beginning as a 

 rule at the anterior or flagellar end, the cleavage plane passing down 

 through the middle of the body. As the halves separate the two 

 daughter cells usually come to lie in one plane so that final division 



Fig. 95. — Euglena nociahilis Dang. Vegetative individual (A) and simple and mul- 

 tiple division within cyst. (After Dangeard.) 



appears to be transverse. In O.ryrrhis marina division is actually 

 transverse (Fig. 43, p. 88), and transverse or oblique in the Dino- 

 flagellida generally. In the majority of forms the individuals divide 

 while freely motile, but this is by no means universal, variations 

 in this respect occurring in the same famil^' and exew in the same 

 genus (see Dangeard, 1901). Thus in Euglenida^ division in the 

 motile state occurs in some species of Euglena {E. liridis, E. genicn- 

 lata, E. flam, etc.), in Peranema, Entosiphon, Menoidium, Astasia, 

 14 



