280 



BIOLOGY OF THE PROTOZOA 



detached and swim about actively until they perish or meet and 

 fuse with a macrogamete. 



A complete differentiation, or oogamy, is shown by the majority 

 of Coccidiomorpha amongst the Sporozoa. In some cases, how- 

 ever, notably in the genus Adelina, gamete differentiation is of the 

 same general type as in the Vorticellidae. In other cases a multi- 

 tude of minute sperm-like gametes are formed from the rnicro- 

 gametocyte while the macrogamete appears like a slightly modified 

 vegetative individual (Fig. 144). In Cyclospora karyolytica, Schau- 

 dinn (1905) maintained that differences shown by the mature garnet - 

 ocytes could be followed back to the sporozoites from which they 



came. 



Fig. 143. 



Epistylis umbellaria; colony with mature macrogametes and micro- 

 gametes and their fusion (m) and (.1/). (After Greeff.) 



In these various cases we find quite variable expressions of differ- 

 entiation in the protoplasm of a given species. This differentiation 

 appears to be cumulative in the life cycle and the same initial 

 protoplasm through differentiation in two directions may, at matur- 

 ity, give rise to both types of gametes. Anisogametes illustrate 

 not only the cyclical differentiation resulting in a different type of 

 reproduction from that of the usual vegetative type, but they also 

 illustrate the two divergent effects which such differentiations may 



