266 
J. 0. Wakelin Barratt and G. Arnold 
considerably compressed and assumes a bell shape. Shortly afterwards 
the vacuolated spermatid disappears, but the manner of its disappearance 
has not been fully traced. Although this enlargement is recognizable 
only in the spermatid it is possible that some of the vacuoles formed in 
connection with spermatocytes of the first order, are, in reality, archo- 
plasmic in origin. 
Archoplasm. The archoplasm met with in spermatocytes of the 
first and second Orders, and in spermatids, is not markedly altered in 
appearance after the application of X rays. Several masses of archoplasm, 
it may be observed, can sometimes be seen in the multinucleated and 
multivacuolated masses. 
Centrosomes. These are normally readily recognizable in sperma- 
tids, but are less easily observed at the spindle poles of dividing sperma- 
tocytes. No structural change was observed, after the application of 
X rays (cp. p. 271). 
Vacuoles. These may be arranged in six groups, the first five 
being nuclear and the last cytoplasmic. 
1. Vacuoles arising in connection with intranuclear bodies (Fig. 14). 
These occur singly in the nuclei of spermatocytes of the first order; thev 
are also seen in multivacuolated cell masses. They contain a large elon- 
gated intranuclear bodv and do not present a definite external membrane. 
In diameter they Vary from about a quarter to more than half the normal 
diameter of the cell. They are completely embedded in the nucleus, 
which is more or less compressed. They have been observed after the 
3rd day. , 
2. Empty vacuoles, not containing an intranuclear body, situated 
wholly in the nucleus, which they compress (Figs. 22, 25 and 26). These 
usually have the same size as the preceding, sometimes, however, they 
are only about 3 u in diameter. They have no cvst wall. They occur 
in spermatocytes of the first and second Orders, and may also be re- 
cognized in some of the multivacuolated cell masses. They have been seen 
only after the 3rd day. 
3. Distended archoplasmic vesicles, provided with a cyst wall (Figs. 23, 
24, 27 and 28). These appear, after the 3rd day, in spermatids and in 
spermatocytes of the second order. They are also recognizable in some 
multivacuolate cell masses. A definite intermediate body cannot be 
recognized. In size they are generallv equal to that of a spermatid nucleus, 
but they may be larger. They compress the nucleus, by which they are 
almost completely surrounded. 
