SEX INHERITANCE 133 
of chromosomes; in some races the male has one 
less chromosome than the female, in other races 
the female has one less than the male. There are 
races in which the male has the haploid (full) 
number of chromosomes, while the female has the 
double number. The gametes giving rise to these 
two kinds of individuals are sometimes loosely re- 
ferred to as male and female, but they are properly 
only male-producing and féemale-producing in certain 
combinations; for, as shown in non-disjunction, the 
same gametes if they form other combinations may 
give a result that is just the opposite from that 
which usually occurs. Thus, a “female-producing”’ 
X-sperm will give rise to a male if it enters an egg 
without an X. 
The same terms male and female have been 
carried over to the protozoa—organisms that are 
one-celled like the gametes of multicellular forms; 
but obviously the words are here used in a different 
sense. In what manner the protozoa are to be 
compared with the higher forms remains uncertain 
until we have more definite information concerning 
the chromatin changes that take place before, 
during, and after, conjugation. 
In the mosses and liverworts an interesting 
situation exists. There are two alternating gener- 
ations, one is diploid (sporophyte), the other haploid 
(gametophyte). In mosses and liverworts with 
separate sexes the sexual generation is haploid. 
Allen has found in one of the liverworts, Sphero- 
carpus, that there is an unequal pair of chromosomes 
