212 MOXOGRAPH OF THE LABOULBExAcE^. 
f^reatcr portion of its length, is more or less abruptly narrowed jnst before passing 
into the venter. The contents of the venter during its active period, as it increases in 
V 
islies through the narrow opening in the diaphragm into the cavity of 1 
neck, and tlie portions thus extruded, when they have reached a certain definite si 
become separated from the mass whence they were derived ; and, assuming the fo 
of short cylindrical rods, the antherozoids pass into 
fi 
■ical rods, the antherozoids pass into the general cavity of the neck, 
diameter of which is but slightly larger than their own, and thence make their 
[ exit through the terminal pore. This process of abjunction, by which small but 
imiform pieces become separated from the contents of the venter as it is pushed into 
the neck, continues for a period which varies somewhat in different cases, but may 
begin some time before the female organs are mature, and continue long after they 
r 
have been fertilized. Although one sees many cases in whicli the neck contains a 
continuous series of antherozoids which are evidently pushing one another out tlirough 
the terminal opening, these bodies seem to be able to make their exit quite inde- 
pendently of one another, although at the same time they also appear to lack any 
indication of a power of independent motion, amoeboid or other. 
As has been already mentioned, the form of the simple antheridium is subject to 
inconsiderable variations which depend in general on the relative development of the 
neck or of the venter, the latter being sometimes short and stout and abruptly dis- 
tinguished, while in other cases it may run gradually into the neck without any such 
clearly marked differentiation. The neck, too, may be short and rather stout, or long 
and slender, straight or curved, the extremes in these respects being illustrated 
J 
such instances as the following: Ldboulhenia declpicns {WxiQ XX, fig. 20), L. Elon- 
gcda (Plate II, fig. 15), Teratomyces (Plate X, figs. 6 and 11), Compsomyces (PUite 
XI, fig. 14), or Stigmatomyces Bam (Plate I, fig. 26). 
The disposition of the antheridia, and their relation to one another on the same 
appendage or branch, is a matter of much importance in affording generic distinctions, 
and even, in a few cases, is of service in defining species. On this basis all the gen- 
era having simple antheridia, with the exception of Amorphomyces, which has in- 
variably a single antheridium, might be separated into two categories: those in which 
the antheridial cells are disposed in definite series on the appendage, and those In 
which they are more or less indefinitely placed. 
In the first category are found forms in which the series is a single one, as in 
Stigmatomyces (Plates I, figs. 8-12 ; VIII, fig. 3), the antheridial cells succeeding one 
another in a single vertical row, while a somewhat more complicated condition exists 
in Idiomyces, where three vertical rows are present (Plate IX, figs. 18-19). Again, 
