152 



ZOOLOGY. 



thus opened up one of the most interesting departments of 

 zoology. It was not until the middle of the nineteenth century 

 that the simple, unicellular structure of the Protozoa was 



FIG. 70. 



FIG. 70. Eudorina. A colony of 16 flagellate cells imbedded in a gelatinous matrix. 



FIG. 71. 



FIG. 71. Eudorina. The development of reproductive bodies within the colony 

 from the ordinary vegetative cells (.v). f, a mass of female cells; m, a mass of male 

 or motile cells; f, a single female cell surrounded by male cells (m') ; w, the 

 boundary of the original colony. 



Questions on figures 70 and 71. 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? 



