CILIATED PITS OF STENOSTOMA 241 
Fig. 2. Later stage of formation of ciliated pit andits ganglion. Note widened 
fundus with its low epithelium that vet has rhabdites (rh). Mitoses (me) in 
region of fundus continue to be present. Ganglion (g) has enlarged. (mes) 
Mesoderm that develops into ‘brain’ and commissure. (end) Endoderm. 
x 1500. 
Throughout the growth of this ganglionic mass of cells their 
nuclei have a constant chromatin pattern. At the earliest ‘ 
and intermediate stages of the development of these cells their 
nuclei tend to be oval while their cytoplasmic bodies are more 
or less elongated, pyriform, or spindle shaped. Figures 1, 2 
and 3. In the final stages of their development the cell bodies 
become less distinct until in the mature ganglion there is only a 
network of fibers or cytoplasmic strands supporting many sphe- 
roidal nuclei. Figure 4. 
