A TEXTBOOK OF PHYSIOLOGY 



I- it; 4. GoNnrji PECTORALE, SHOWING THE INDIVIDUALS. (From Dahlgren and 

 Kepner, after Stern.) 



FIG. 5. VOLVOX GLOBATOK, A COLONY OF CELLS IN WHICH ALL THE CELLS ABE CON- 

 FINED TO THE SURFACE OF THE SPHERE, LEAVING A CAVITY INTERIORLY. (From 

 Dahlgren and Kepner, after J. H. Emerton.) 



The cells are united by protoplasmic strands radiating from each cell. The dif- 

 ferentiated cells, or ova, are shaded dark. 



