22 



EDWIN LINTON. 



lows that approximately the same amount of yolk is thus dis- 

 charged at each contraction. The mass of yolk is propelled with 

 comparative rapidity along the short vitelline duct (/f) towards the 

 median line. This duct passes near the anterior border of the 

 germarium (o), where it is joined by another short duct (c) from 

 the germarium. As the mass of yolk was passing the germarium 

 it was noticed that a number of free nucleated cells, which 

 appeared to be lying loosely in a median area (/) of the ger- 

 marium, were set in oscillatory motion. It was quite evident 



Figs. 2, 3, 4. Diagrams showing different stages of egg-making. 



Fig. 2. An egg {e) has just been discharged from the oviduct (ot/). A mass of 

 yolk for the next egg is collecting in a muscular lobe (a) of the yolk reservoir and 

 is about to be ejected through the short duct {d) into the common duct {cd). 



Fig. 3. The mass of yolk (j) has entered the common duct {cd) and its suction 

 is probably an inciting cause of a germ's entering the common duct from the germ- 

 duct («). The direction of movement of yolk and germ is shown by the arrows. 



Fig. 4. The mass of yolk has passed by way of the common duct to the ootype 

 (em) where it has been molded into a tetrahedral shape and a shell has been depos- 

 ited around it. A cluster of spermatozoa (j) has been injected into the common 

 duct (ra') from the muscular seminal duct (5^/) at its opening (sd^) and has pro- 

 ceeded a short way towards the ootype. The arrow shows the direction of movement 

 of the spermatozoa. In the process of egg-making the egg is discharged from the 

 ootype a very short time (one or two seconds) after the spermatozoa have arrived at 

 the ootype. 



that the agitation of the germ-cells was due to the passage of 

 the mass of yolk from the vitelline reservoir. While it was 



