ZOOLOGY 



1 some cases the conjugating cells are of two sizes, union always 

 iking place between a large cell or mfgaganutc and a small cell 



iG. 57. — Heteroxnita rostrata. A, the positions assumed in the springing moTements 

 of the anchored form; B, longitudinal fission of anchored form; C, transverse fission of 

 the same ; D, fission of free-swimming form ; E, conjugation of free-swimming with anchored 

 form ; W>, zygote ; E6, emission of spores from zygote ; F, development of spores ; ii.l, ante- 

 rior ; /.^, ventral flagellum. (From Parker's Biology, after Dallinger.) 



r microgamcte. In Volvox (Fig. bQ) this dimorphism reaches its 

 xtreme, producing a condition of things closely resembling what 



