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observers in certain members of the following divisions of the animal 
kingdom: Mollusca, Rotifera, Arthropoda, Amphibia, Aves, and Mam- 
malia, including man himself (in the latter by von LA VALETTE 
ST GEORGE, K. VON BARDELEBEN and VON WIDERSBERG). In animals 
belonging to the aforesaid groups its occurrence has been put on record 
in more than 36 species. But all observers agree, that it is never 
functional. 
It is the task of the functional spermatozoon to bring about the 
effects due to what WEISMAnN has termed ‘‘amphimixis”. Since it 
is the egg, which develops, and not the sperm, the burden of provid- 
ing for the continuance of the race falls upon the female Metazoon, 
or, rather, upon the germ-cells, of which it is the host. To carry 
out this duty the differentiation of twofold gametes, the male-eggs 
final result is, that each spermatid, resulting from the second mitosis, 
contains but one chromosome. The normal number of chromosomes in 
Paludina is, according to Meves, 14, the reduced number 7. Here 
therefore, instead of 7 chromosomes each spermatozoon contains but 
the equivalent of one. In Pygaera, according to the same observer, 
in the formation of the non-functional form of spermatozoon chromatic 
material, in other words chromosomes, find no place, “in Pygaera the 
second form of spermatozoon is completely destitute of nuclear portion, 
that is, it is headless’ (Mevzs). Notwithstanding Mervszs’ cautiously 
expressed opinion to the contrary, there would appear to be no escape 
from the conclusion, that, even the complete differentiation of the second 
form of sperm in Paludina und Pygaera being accompanied by phenomena, 
only diagnostic as degenerative, it can be of no functional import 
whatsoever. 
When, therefore, I state, that evidences of degeneration are always 
to be found in the development of a second form of sperm, and that 
these and other evidences, i. e., actual experience, always and invari- 
ably point to its non-functional nature at the present time, this con- 
clusion is in accordance with the strictest canons of scientific investi- 
gation. The opposite view would be not only contrary to all experience 
but, apparently, incapable of proof. “But”, it may be asked, “may not 
some one or other of the 250000 species of insects possess two forms 
of functional spermatozoa?” This is exceedingly unlikely, and it would 
not fit in with the homogeneity of the reproductive processes of the 
Metazoa as they now exist. One might as well hope to meet with 
cases, in which the polar bodies of oögenesis were normal functional 
gametes or eggs. Neither contingency is, of course, impossible, only 
highly improbable, for what has been in the past may, so far as our 
very limited knowledge and intelligence extend, happen again in the 
future. Neither occurrence would merge into the miraculous, as is the 
case with the supposed conversion of males into hermaphrodites. We 
may neither limit Nature’s powers, nor seek to make her perform miracles. 
PES ee 
