LIST OF ILLUSTRATIONS 



FACING PAGE 



Parts of Paramecia showing cilia and trichocysts ... 62 

 A section from the region of the mouth of Paramecium showing 



the formation of a food vacuole 66 



Binary fission of Paramecium aurelia 66 



Diagram illustrating the life history of the malarial fever parasite 89 

 Volvox globator . . ... . . . . between 96-97 



Volvox globator between 96-97 



Examples of various kinds of tissues 100 



Figures illustrating four different kinds of cleavage . . . 109 



Regeneration and grafting in Hydra 137 



Physalia, the " Portuguese man-of-war " 143 



Regeneration of Planar ia maculata 157 



Longitudinal vertical section through the anterior portion of an 



earthworm 168 



Stages in the embryology of the earthworm 185 



Regeneration in the earthworm 189 



Grafting in the earthworm ... .... 190 



Semi-diagrammatic view of internal organs and appendages of 



right side of a male crayfish 195 



Surface of a crayfish egg with embryo beginning to form . .216 

 Embryo of the crayfish in the Nauplius stage . . . .216 



Older embryo of the crayfish 216 



Head of worker honeybee 235 



Legs of worker bee 237 



Sting of the worker bee 239 



The respiratory system of the bee 243 



The nervous system of the bee 244 



Female reproductive organs 249 



ni 



