52 MARCUS M. HARTOG. 
In the present case the trophoplasm eliminated from the 
nucleus passes into the cytoplast, and is utilised, not ex- 
creted. 
The chromatic elements of the nucleus now become more or 
less free, and in anticipation of two mitoses undergo two suc- 
cessive longitudinal fissions.' This is, as O. Hertwig shows, 
only an anticipation (comparable with precocious segrega- 
tion in embryonic development) of the subsequent mitoses, 
which follow one another in rapid succession with no in- 
terval of rest in the vesicular state separating the first 
from the second, as is usually the case between two successive 
mitoses. 
The nucleus is at this time peripheral. A mitotic spindle 
is formed with its axis concurrent with that of the ovum. A 
very uneven cell division now takes place, the smaller cell 
being apparently budded off from the larger, which retains the 
name of the ovum, the smaller being termed the “ first polar 
body.” The nucleus of the first polar body then passes into a 
resting state in some animals. What we may term the 
secondary nucleus of the ovum at once forms a second spindle, 
and a “ second polar body” is budded off like the first. The 
nucleus produced in the egg by this second mitosis is the 
gametonucleus, the egg being now converted into the 
oosphere. In most animals* the process is made symmetrical 
by the division of the first polar body into two. In this case 
the brood consists of four gametes, three arrested and one 
functional. When three polar bodies are thus formed the 
nuclei of all four cells are exactly similar and equivalent. 
The only difference between the polar bodies and the oosphere 
lies in their cytoplasts. Adopting the usual nomenclature of 
mother- and daughter-cells, the relationships here may be 
noted thus: the oosphere and second polar bodies are sisters, 
1 This account is taken from Ascaris megalocephala. It is by no means 
certain that the peculiar characters of the two mitoses here are universal, 
though they have formed the chief morphological base for a very big theory. 
Similar “anticipated” mitoses, however, occur in spermatogeny also. 
® Coelenterates, Molluscs, Vermes, and Vertebrates, according to OQ. 
Hertwig. 
