690 CLARENCE L. TURNER 
resembles the testis of the Amphibia in so far as there is a lack 
of seminiferous tubules and in the presence of lobules which be- 
come divided up into cysts as soon as the maturation process 
has begun. While the amphibian testis undergoes a seasonal 
change, there is no such seasonal variation in volume as there is 
in the perch. There is also an anteroposterior seriation in the 
testis of the urodele, while the testis behaves as a unit in the 
perch. 
It is evident from only a cursory examination, however, that 
there are variations in different teleosts which differ considera- 
bly from the course of the changes which occur in the perch. 
After some germ cells have migrated to the periphery of the 
testis in the perch there is-a proliferation which ‘increases their 
number. There is also a constant addition occasioned by the © 
arrival of new migrating cells. This process continues until there 
is a solid cord of germ cells which fills each lobule of the testis 
at its normal small size (early August). Some connective- 
tissue cells. are found among the germ cells. The transformation 
of the germ cells into spermatogonia is contemporaneous with 
the beginning of the increase in the volume of the testis (late 
August). After spermatogonia are formed the process of sper- 
matogenesis takes place rapidly and the volume of the testis 
increases apace. The spermatogonia arrange themselves into 
cysts which are imperfectly divided by connective-tissue cells. 
Each cyst behaves as a unit during the maturation process, all 
of the cells passing through the same stage at the same time 
(figs. 25 and 26). The cysts at the center complete their mat- 
uration and form spermatozoa first, but there does not seem to 
be any definite seriation from the center to the periphery of the 
lobule. 
The formation of cysts within the lobules is not as clearly 
shown in the perch testis as it is in the testis of the sunfish 
(fig. 24). There is a close resemblance between the cyst forma- 
tion in the testis of these teleosts and in the testis of many 
arthropods. 
When the germ cells first become lodged at the periphery of 
the testis in the perch they form a lens-shaped mass which 
