141 
Fig. 1. Sketch of an Amphiura 
in its spawning position. 
The normal position of these Ophiurids is, as stated above, 
this that the disk is completely buried in the mud, lying as in a 
bed about two—three centimeters below the surface of the mud, 
only the arm-points rising over the surface. When they want to 
discharge their sexual products, they rise over the surface of the 
mud so that the disk is kept about two centimenters above the 
surface, resting on the five armbases as pillars, the armpoints at 
the same time disappearing below the 
surface (Fig. 1.). The disk was generally 
kept more or less obliquely. While in 
this position, the sexual products are 
streaming out of all the bursal slits. The 
males were the first to discharge their 
sperm, which spread in the water around 
them as a white cloud; having finished 
discharging the sperm they gently sank 
down into the mud, assuming again their normal position. Very 
soon after they had disappeared, not more than a few minutes 
after, some females rose over the surface of the mud exactly in 
the same way as the males and at once began to shed their eggs, 
which feli to the bottom, where they formed a distinet red layer; 
immediately after having discharged the eggs the females went 
down into the mud again in the same way as the males. It might 
perhaps be suggested that the oblique position of the disk during 
the shedding process is of some importance, it being avoided in 
this way that the eggs are buried in the mud by the sinking 
body, lying not direetly below the disk. However, conditions in the 
natural surroundings may perhaps afford sufficient safeguard against 
a burying of the eggs, and I do not venture to maintain that the 
oblique position of the body is more than quite a casual circum- 
stance. 
It was ascertained by examining such specimens which had 
just discharged their sexual products that they were quite empty t 
all the sperm and the eggs being discharged at the same time. 
Shortly after the eggs had been discharged a number of them 
were taken up with a pipette and placed in a separate dish in 
order to trace their development, which could, of course, not be 
done in the aquaria with the running water. Evidently, I had taken 
