150 Harry Lewis Wieman. 



In L. signaticoUis, at the appearance of the semi-fluid condition 

 described at the junction of the egg tube with its stalk, the germ 

 cells exhibit signs of amoeboid movement and move away from 

 each other; the first step in the process being shown in Fig. 9. 

 The young eggs are just entering the growth period, and are taking 

 positions in a linear series. As they separate they leave behind a 

 strand of protoplasm which comes into relationship with the nurse 

 cells through the medium of the matrix. Fig. 11 is a rather for- 

 tunate section showing a number of egg strings in various degrees 

 of development. It should perhaps be stated that in Fig. 11 

 the distal end of the ovariole is toward the bottom of the page, 

 whereas in Figs. 6, 7, 8, and 9 the distal end is toward the top 

 of the page. 



These nutritive strings are very delicate structures composed 

 of thin strands of the cytoplasm of the egg, drawn out like pseudo- 

 podia, and owing to their transparency, are very easily overlooked. 

 At the points where they connect with the nurse cells, the strings 

 blend with the intercellular region. 



The nurse cells as shown in Fig. 11, are large polynuclear cells, 

 between which the egg strings terminate. The groove-like spaces 

 between the nurse cells can be compared to ducts into which the 

 nutritive material from the nurse cells is secreted, and from which 

 it is taken by the egg strings into the egg. 



As the eggs pass from the semi-fluid region they come into 

 contact with the columnar cells of the tube stalk which form the 

 follicles. After the eggs have taken up their positions, one behind 

 the other in their respective follicles, we find that each string 

 leaves its egg laterally and finds its way back through the follicle 

 cells to the nurse cells (Fig. 12). This figure shows the egg string 

 at the height of its development. Later it disappears and no trace 

 of it can be found in the mature egg. 



The real growth period of the egg is initiated with the formation 

 of the nutritive string, and shortly afterward the egg moves down 

 into the tube stalk probably by amoeboid movement or peristaltic 

 action of the ovariole, or both. Korschelt ('86) observed peristal- 

 tic movement when the egg tube of Dytiscus marginalis was 

 placed in physiological salt solution. I have examined fresh ovaries 



