153 



The results of the measuring of 100 eggs in different stages of 

 development and taken from different animals, after preservation 

 in a mixture of forniol and sea-water (25 : 975) are the following: 



Diameter in niM. 1,11 1,10 1,09 1,08 1,07 1,06 1,05 1,04 1,03 1,02 1,01 1,00 0,99 0,98 0,97 0,96 

 number of eggs 5 4 5 10 9 07 11 11 6 6 2 1 1 1 1 = 100. 



D=l,06 A = 1,066. 



Of these hundred eggs fifty were in the earliest developmeutal 

 stages, viz., during cleavage, or unfertilized, fifty were killed after 

 the blastopore was closedo 



When we divide the eggs according to their stage of develop- 

 ment, we get the following curious results: 



first fifty (early developmental stages) : 



niM. 1,11 1,10 1,09 1,08 1,07 1,06 1,05 1,04 1,03 1,02 1,01 1,00 0,99 0,9S 0,97 



number of eggs: 2 10 22 16 6 74 5 2 1011 = 50. 



second fifty (advanced stages): 



mM. 1,11 1,10 1,09 1,08 1,07 1,06 1,05 1,04 1,03 1.02 1,01 1,00 0,99 0,98 0,97 0,96 



number of eggs : 33587 11 5421 000001 = 50. 



In both series the size of the greatest frequency (mode = dich- 

 teste Werth. ïïeincke und Ehrenbaum) is 1,06, but in the first case 

 the greater part of the eggs measure less than 1,06 mM., in the 

 second case the greater part of the eggs measure more. 



The curves drawn from these figures are not at all regular, at 

 least that of the younger stages of development, but nevertheless 

 they seem to point at a slight increase of size of the eggs 

 during development. However, the number of eggs measured is 

 too small and especially the number of eggs of the same indivi- 

 dual measured, so there cannot be drawn any sure evidence from 

 these figures. 



As most buoyant eggs the eggs of Trachinus draco are perfectly 

 transparent, and are protected by a rather tough membrane. This 

 capsule bas a peculiar structure. It seems to be composed of two 

 layers. The inner membrane is minutely wrinkled, the ridges 

 interdigitating with each other in a complex manner, and covering 

 the entire surface of the egg with a system of fine interlacing 



