180 RAYMOND BINFORD 
A spireme and synapsis occur in connection with the first miotic 
division. ‘The second mitotic division follows soon after the first. 
4, In the mature spermatozoon the protoplasmic portion, con- 
taining the nucleus, is cup-shaped. From the rim of the cup 
pseudopodia project like the rays of a star. There is a capsule 
half-imbedded in the cup. An inturned tubule is connected 
with an opening in the distal portion of the capsular wall, and a 
rod-like central body arises from the proximal side of the capsule 
and projects into the inner tubule. 
5. In the transformation of the spermatid, the nucleus becomes 
uniform in consistency, reduced in size and cup-shaped. <A mito- 
chondrial ring is formed between the nucleus and the capsule. 
The capsule arises as a vacuole in the cytoplasm. In the course 
of its development it shows an increasing affinity for nuclear 
stains. 
6. The central body develops from a granule which appears 
on the proximal side of the capsule. The inner tubule is formed 
from two vesicles which arise at the distal end of the central 
body. 
7. Hypotonic solutions of various salts and possibly other 
stimuli cause a lengthening of the central body, an eversion of 
the inner tubule and an inversion of the wall of the capsule. 
8. When the spermatozoa come in contact with the egg under 
normal conditions, the capsule is usually applied to the shell of 
the egg and the nuclear cup is directed away from the egg. In 
this position eversion takes place and the ejected central body, 
the inner tubule, and the capsule with its contents are thus 
turned through the shell into the egg. 
9. The nuclear cup is left on the outside of the egg; it soon falls 
off. 
