2,66 Bower. — On antithetic as distinct from 
be found either in animals or plants : there is, as far as I 
am aware, nothing which corresponds to it in the animal 
kingdom, while among plants, though such developments as 
those above referred to in the Confervoideae, Florideae, and 
Ascomycetous Fungi may be noted as occupying a similar 
position in the life-cycle, they need not be accepted as strictly 
comparable. Thus the phenomena which accompanied, or 
we may rather say conduced to, the rise of the higher sub- 
aerial forms of plants from the lower aquatic types, stand 
alone in the organic world. 
As regards terminology, what has been above written calls 
for very little change : the main points have been satisfactorily 
settled by De Bary 1 , and his definitions of spore and carpospore 
will stand. I would suggest, however, as an important addi- 
tion too long deferred, that we should adopt the terms a7itithetic 
alternation and homologous alternation in the sense in which 
they were introduced by Celakovsky 2 : by so doing the true 
alternation of sporophyte and gametophyte is distinguished 
from the much less distinct phenomena of alternation in animals 
and in certain of the lower plants : thus alternations would be 
classified as follows - 
(a) Antithetic alternation of two generations phylogeneti- 
cally distinct, i.e. where a new stage (sporophyte) has 
been interpolated between pre-existing generations 
(gametophytes) : this has probably arisen independently 
in several distinct phyla, and the results are to be re- 
garded as not perfectly comparable with one another. 
(i) In the Archegoniatae. 
(ii) In the green Confervoideae, &c. 
(iii) In the Florideae. 
(iv) In the Ascomycetous Fungi. 
( h ) Homologous alternation of two or more generations phylo- 
genetically similar to one another, but differing in the 
presence or absence of sexual organs. To such alter- 
1 Fungi, pp. 1 19, &c. 
2 Sitz. d. k. Ges. d. Wiss. in Prag., 1874, P- 3 °* 
