PLATE VI. 
All figures were drawn with a camera lucida, using a Leitz immersion 
objective combined with ocular 4. The magnification here given is about 1500 
diameters. 
Fig. I. Colony of Spondylomorum. General habit. 
Fig. 2. Individual cell from colony. 
Fig. 3 and Fig. 4. Longitudinal sections of adult individuals. 
Fig. 5. Longitudinal section of cell immediately after nuclear division. 
Fig. 6. Cell in transverse section, after first division. 
Fig. 7. Group of cells after second division. Four-celled stage. 
Fig. 8. Eight-celled stage, in nearly transverse section. 
