174 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. . 
single case sections showed an apparent exception, the spermatozoon 
having entered an egg while it was still within the medusa, and before 
the polar cells had been detached. Figure 18 (Plate 2) represents the 
condition referred to; the smaller vesicle appears to be the sperm 
nucleus, the larger one has every appearance of a germinative vesicle. 
As arguments that the latter is such, the following points may be sug- 
gested: (1) the egg nucleus is usually not so close to the periphery of 
the egg; (2) the size and shape of the nucleus are characteristic of 
germinative vesicles just before the first maturation spindle forms 
(Figs. 5, 7); (3) at least one, and possibly two, astral centers are pres- 
ent (somewhat like Figure 7), a condition not usually found accom- 
panying egg nuclei; (4) other eggs in the same medusa had their nuclei 
in a condition which precedes the formation of the maturation spindles. 
Sections show that while the spermatozo6n may enter the egg at any 
point, it more commonly enters rather close to the egg nucleus (Fig. 
18). ‘The cones seen at the surface of living eggs may also be recog- 
nized in those which have been fixed (Figs. 17a, 19b), though this is 
not always the case (Figs. 18, 19c). Sections of eggs which showed 
this cone also showed a spermatozo6n or sperm nucleus, consequently 
the cone is to be considered as an entrance cone (Wilson, :00) rather 
than a true attraction cone. 
Sometimes there is located in the periphery of the egg, and extending 
from its surface to the sperm nucleus, a differentiated, funnel-shaped 
region (Figs. 17a, 20a), which one naturally refers to the influence 
of the spermatozoén. Sometimes the axis of the funnel or cone- 
shaped region is straight and nearly radial (Fig. 17a), at other times 
it is more or less curved (Fig. 20a), but its apex coincides with the 
sperm nucleus, and its broad basal end is always at the periphery of 
the egg. Similar phenomena, apparently due to similar causes, have 
been observed in other eggs. They are especially prominent in the 
eggs of certain amphibians, where the pigment renders the condition 
more obvious (Schultze, ’87, Fick, ’93, King, :01), and have also 
been observed in the earth worm (Foot, ’94), in echinoderms (Wilson, 
’95), etc. An angle has sometimes been found in this “track”’; it 
was interpreted by Roux (’87) as the end of the “entrance path,” 
after which the sperm comes under the influence of the egg nucleus 
and moves toward this in the “‘copulation path”; while Fick considered 
the angle due to the rotation of the spermatozodn. The “‘track”’ 
in Pennaria never showed this angle, and as a rule was nearly radial 
and short, leading directly to the egg nucleus, which was usually 
near the point of entrance of the sperm. In many cases no “‘track”’, 
