144 THE CHROMOSOMES 
cytoplasm does not here affect the character of the 
larve, it is rational to suppose that an increase such 
as is present in the giant eggs likewise produces no 
such effects as observed in the larve. At the same 
time, normal eggs were cross fertilized and in the 
two-cell stage the blastomeres were separated. The 
contributions by the two parents were relatively the 
same as in the normal egg. These larve were like 
those from egg fragments, and serve as a control of 
those larve in so far as they bear on the question of 
how far size alone may affect the result. Moreover, 
in them, the relation of the chromosomes to the 
cytoplasm is the same as in the normal egg (whether 
the sperm does or does not bring in cytoplasm). 
Hence, since the amount of cytoplasm is shown to 
have no influence on the character of these larve, 
there is no reason for supposing that it had any 
influence in the case of the giant eggs. 
Boveri’s studies upon dispermic fertilization of 
the egg of the sea urchin bear directly upon the 
question at issue. He found that when two sperm 
simultaneously enter the same egg, each brings in a 
centrosome, so that a tetra- or tri-polar spindle is 
formed for the first division, as shown in Fig. 37. 
Instead of a double set of chromosomes, as in normal 
fertilization, there are three sets. At the first 
division, the chromosomes are irregularly distrib- 
uted upon the multipolar spindles. In consequence, 
some cells may get one of each kind of chromosome, 
while other cells may get less than a full complement 
(Fig. 38). These dispermic eggs almost always give 
