On the Spermatophores of Octopus Americana. 43 
among the other spermatophores in the spermatophoric sac, and as 
they move aboral end first toward the penis these threads are in 
position to be pulled when the spermatophores leave the penis. 
Arrangement near the base of the penis indicates that a single 
spermatophore is ejected at a time. 
When the cap thread is pulled the cap immediately begins to swell 
and elongate (fig. 7), and the evagination of the ejaculatory apparatus 
begins. The cap soon goes to pieces (fig. 8) and evagination continues. 
The middle membrane is very pliable and is extended far beyond the 
point of folding back (figs. 7, 10, 11, and 14 pr). 
The hyaline core is composed of two parts, a central core (Hc’) 
that is quite liquid mixes with the water and disappears, and an outer 
part (Hc) that sticks to the inner membrane forming small projections 
and lumps (figs. 7, 12, and 15) that change form considerably as 
ejaculation is continued. 
At the beginning of evagination the spiral coiling of the ejaculatory 
apparatus begins to straighten out. The loops nearest the cap are 
affected first, and little change is noticeable in the positions of other 
parts in the spermatophore until all these coils have been straightened 
(figs. 11 and 12). The twist in the ejaculatory apparatus is shown 
again in evagination by the spiral into which the tube is again thrown 
at the evaginating extremity (figs. 11, 12, and 13). When a position 
about equivalent to the point 4, figure 1, is reached the act of evagina- 
tion is slowed down considerably. This is probably due to resistance 
offered by the spiral filament which here becomes better developed. 
The slowing and the torsion developed by evaginating the spiral fila- 
ment result in swelling the evaginating end of the tube, crowding and 
spirally coiling the aboral end of the ejaculatory apparatus into the 
swelled portion, and in uncoiling the sperm thread and pressing it 
forward into the part of the tube that has evaginated (fig. 16). 
The resistance to evagination becomes greater in the region where 
the spiral filament is best developed and the swelling of the evagin- 
ating end is correspondingly increased. This continues until the 
sperm thread reaches the portion of the ejaculatory apparatus that is 
still to evaginate and becomes crowded along its sides. 
When evagination reaches the point where the middle membrane 
thins and disappears it becomes very much more rapid, the remainder 
is turned rapidly, and the sperm thread immediately begins to escape 
through the open evaginated end of the ejaculatory apparatus. It 
commonly happens (fig. 17) that the ejaculatory apparatus ruptures 
near its narrowed extremity and that the escape of the sperm thread 
takes place through this rupture. 
The escape of the sperm thread is even, not hurried, and continues 
for a minute or more. It begins while a considerable portion of the 
aboral end is still closely coiled. The coils open one after another and 
