i6o 



ZOOLOGY 



A naturalist of Holland, Leeuwenhoek, first discovered the 

 Infusoria, and thus opened up one of the most interesting 



Pig. 72. 



Fig. 72. Eudorina. A colony of 16 Sagellate cells imbedded in a gelatinous matrix. 



Fig. 7 



Fig. 73. Eudorina. The development of reproductive bodies within the colony from the 

 ordinary vegetative cells (f). /, a mass of female gametes; m, a mass of male or motile gametes; 

 /', a single female gamete surrounded by male gametes (m') ; w, the boundary of the original colony. 



Questions on figures 72 and 73. — What suggests that this is a colony rather 

 than an individual? What suggests the reverse? Compare accounts in other 

 texts to test your conclusions. What degree of differentiation is shown among the 

 cells? 



departments of zoology. It was not until the middle of the 

 nineteenth century that the simple, unicellular structure of 



