EMBRYOLOGY OF STOMOTOCA APICATA 335 
THE EGG 
The egg of Stomotoca apicata is spherical and measures. 14 
of a milhmeter in diameter. It is devoid of a membrane and the 
cytoplasm is rather dense and only semi-transparent; however it 
is not as dense as the egg of Stomotoca rugosa, which is extremely 
opaque and of a chalky white color, and also shghtly larger. The 
color of the egg of Stomotoca apicata is a bluish-white. 
A point of interest may be mentioned in this connection. On 
one occasion, when I had taken a number of Stomotoca in the 
tow at night, they were picked out and put into a dish of clean 
sea-water with the intention of allowing them to lay and using 
the eggs for study the next morning. It happened that both 
species of Stomotoca that are found at Beaufort were represented. 
There were mature females of both species that deposited their 
eggs the next morning at the regular period; Stomotoca rugosa 
has the same time of dehiscence as Stomotoca apicata. Only 
the eggs of the latter species developed; there being no males 
of Stomotoca rugosa. The next day when the two species were 
in the same dish, and both discharged their eggs, only the eggs 
of Stomotoca rugosa segmented and developed. In this case 
there were no mature males of Stomotoca apicata. These facts 
aroused my interest and on several later occasions I placed the 
two species together with the intention of getting them to inter- 
breed, but did not succeed and therefore I am led to the conclu- 
sion that they will not cross even though they are species of the 
same genus. To my knowledge no other experiments have been 
made in attempting to cross different species of this group of 
animals, and I did not have the opportunity to try with any other 
species than the above named after my attention had been called 
to the fact that they did not cross when accidentally placed in a 
dish together. 
POLAR BODIES 
Soon after the egg is deposited the first polar body is given off. 
A few minutes later the second polar body is formed. They 
remain near the egg for some time, frequently until after the sec- 
