232 THE AMERICAN NATURALIST.: (VoL: XXXIX. 
zoölogists have been able to do in some favorable animal types 
(Montgomery, Sutton, Moenkhaus) The chromosomes divide 
longitudinally in the usual way, the halves being drawn apart 
from the points of attachment of the spindle fibers (Fig. 17, e). 
It is clear that each daughter nucleus receives a full set of 24 
daughter chromosomes, 12 of paternal and ı2 of maternal 
origin, and that there is about an equal amount of chromatin 
from each sex. 
It should be especially noted that in the process of fertiliza- 
tion in the pine there is at no time present wbat is generally 
called a fusion nucleus, 7. e, a single nucleus whose membrane 
incloses all the material of both male and female gamete nuclei. 
Such fusion nuclei, as we shall see, have been reported many 
times in other groups of plants than the gymnosperms where in 
many cases, however, detailed studies are very difficult and can 
scarcely be said to have even approached our knowledge of the 
pine. 
Studies of other botanists indicate that the gymnosperms 
generally will show essentially the same conditions as in the 
pine. Thus Woycicki ('99) distinguished in Larix two groups 
of chromatin which he regarded as paternal and maternal. And 
Murrill (: 00) states for Tsuga that the chromatin of sperm and 
egg remain separate, forming two spirems, and only after their 
segmentation into chromosomes are the two sets of structures 
brought together in the first cleavage spindle. Land (: 02) 
figured the sperm nucleus of Thuja imbedded in a depression of 
the egg nucleus. Miyake (:03a) noted that the sperm nucleus 
of Picea became more or less imbedded in the egg nucleus while 
the nuclear membrane remained intact, and the same author 
(Miyake, :03b), reports similar conditions in Abies. Robert- 
son (:04) figures the sperm nucleus of Torreya lying within a 
depression in the female and with a large amount of granular 
cytoplasm (kinoplasm) at the side. Coker (103) states that 
the partition between the gamete nuclei of Taxodium “ does 
not entirely disappear until immediately before the first divi- 
sion " although the two structures are closely united for some - 
time previously while they pass to the bottom of the egg. 
Lawson, studying Sequoia (:04a) reports gamete nuclei of 
