in Li Hum Mar tag on: II. Spermatogenesis . 189 
in question differ from a vegetative division in the number 
of chromosomes, and in no other respect. They may properly 
be called homotype. The same term is equally applicable 
to the three later divisions of the spermatogenetic series. 
The first division of the pollen-mother-cell nucleus in 
Lilium Martagon is similar in every detail to that of the 
primary embryo-sac nucleus. Both divisions exhibit a type 
of karyokinesis differing very widely from that of vegetative 
nuclei. The difference is sufficiently great to justify the use 
of the term heterotype. 
In a communication at a recent meeting of the British 
Association (Liverpool, 1896), I attempted to define the 
difference between these forms of karyokinesis in the par- 
ticular case of Lilium Martagon 1 . My observations on its 
spermatogenesis were not then completed, and only three out 
of the four nuclear divisions from that series were described. 
Now that the details of all the critical nuclear divisions on 
either side have been published, we have the materials for 
a detailed comparison of the two types in this one instance. 
Such a comparison may be of value as a basis for future 
generalisation, for the terms heterotype and homotype have 
only lately been adopted by botanists. They have a definite 
meaning, and it is time that their use should be sanctioned 
if the zoological analogy can be maintained, or that equivalent 
terms should be found if such analogy is misleading. The 
first step to this end is that the botanical meaning of the 
words should be clearly defined. 
Little need be said as to the fixing and staining methods 
which have been applied to the anther. In the main they 
resemble those which were found suitable to the ovule 
(I, p.450, and Appendix). I have maintained the practice of 
arranging the preparations in two parallel series, one pre- 
pared from material fixed in absolute alcohol, the other from 
material fixed in one of the osmic acid mixtures. As the 
tissues of the anther are more easily penetrated than those 
of the ovule, it has been possible to make greater use of 
1 Report of the British Association, 1896, p. 1021. 
