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Charles E. Allen 
no longitudinal split appears until the stage of the “second contraction”. 
The chromatin aggregates in certain parts of the spirem, and six chromosomes 
appear, having the eharacteristic heterotypic forms. The chromosomes 
divide transversely in the equatorial plate. The spindle is broad-poled; 
there are no centrosomes or polar radiations. The telophases are quiekly 
followed by the homoeotypic division, which resembles the typic mitoses. 
E. and E. Marchal (1909) find that the reduced ehromosome nmnber 
occurring in the ordinary sporc formation of Amblystegium serpens is ten 
to twelve. Eighteen to twenty-two chromosomes appear in the hetero- 
typic and homoeotypic divisions of sporophytes of the same species which 
arise, presumably as a result of fertilization, upon gametophytes which 
in turn were produced by regeneration from wounded portions of young 
sporophytes. The somatic number, also, in sporophytes of the new type 
is about twice that in the ordinary sporophytes. The authors conclude 
that the gametophyte regenerated from an immature sporophyte has 2 n 
instead of n chromosomes; that from the fertilized eggs of the new gameto- 
phyte, sporophytes arise with 4 n chromosomes; and by regeneration 
from the latter, gametophytes are produced with, presumably, 4 n chromo- 
somes, tliough no observations are reported upon tliis point. These 
views as to the relative ehromosome numbers in the artificially produced 
races are corroborated, in a number of species, by measurements which 
show that the volumes of nuclei and c-ells in the gametophytes supposed 
to have 2 n chromosomes are about twice those of nuclei and cells in the 
corresponding organs of gametophytes with n chromosomes. 
Some of the more important results of the present investigation 
have already been briefly reported (Allen, 1908, 1911). 
Terminology. 
For the organ in which the male gametes are produced, I shall use 
Bischoff’s (1835) generallv accepted term, antheridium. It is unfortu- 
nate that the same name is commonly applied to the male organs of 
many thallophytes, which, at least in the great majori ty of cases, can 
have no possible homology with the antheridia of bryophvtes and pterido- 
pliytes. Since the term was first used in Connection with the bryophytes, 
it seems best to retain it in this group and to adopt a new designation 
for the antherozoid-producing organs of algae and fungi. 
For the male gamete itself, the term antherozoid (Derbes and 
Solier, 1850) will be used. There is perhaps no serious objection to the 
adoption of the word spermatozoön from the zoologists, although our 
