PLATE 7 
EXPLANATION OF FIGURES 
26 Removal of external part of the spermatozo6én by centrifuging in an advanced 
stage of penetration (cf. fig. 7). History: centrifuged 7200 revolutions in forty 
seconds, fifty minutes after insemination. Preserved fifteen minutes later. 
27to31 Toshow early penetration of injured or partialspermatozoa. History: 
centrifuged 7200 revolutions in forty seconds, fifty minutes after insemination. 
Preserved fifteen minutes later. 
27 Part of the spermatozoén has entered. The remainder is shown external to 
the membrane. The internal part is definitely dividedintwo. Rotationis begin- 
ning. 
28 The part of the spermatozoén external to the membrane is nearly separated 
from the internal part, which is itself definitely divided in two. All parts a little 
swollen as shown by the tone of the stain. The rotation of the cone is beginning. 
29 The internal part is apparently breaking off from the much larger external 
part of the spermatozoén. Cone in process of rotation. 
30 A case in which only a small part of the spermatozo6én has entered; the rest 
of the spermatozoo6n is lost. It represents alater stage of an injury similar to that 
shown in figs. 20 or 21. 
31 <A case similar to fig. 30. 
32 A somewhat later state of rotation of the cone than shown in preceding fig- 
ures. History the same. 
33 aand 33) Twosuccessive sections of the same egg; the parts of the spermato- 
zoon shown in the two sections are entirely separate. The proximal larger part 
(33 a) is proceeding with its rotation and development, leaving the base of the 
sperm head and the middle piece behind. History same as figs. 27-31. 
34 Penetration stage of a sperm remnant preserved fifteen minutes after centri- 
fuging. 
40 Two partial sperm nuclei with asters associated with a single cone. Prob- 
ably a later stage of a condition like that shown in figs. 27 or 28. 
