682 CLARENCE L. TURNER 
stage in which the germ gland is first formed. The interest has 
centered principally about the location in which the germ cells 
apparently originated, in their active migration, in the paths 
traversed in reaching their final place of lodging, and in the 
number which entered the germ glands. Eigenman (’92, ’96), 
Wheeler (99), Dustin (07), Beard (00, ’02), Woods (’01), 
Jarvis (08), Allen (’06, ’09), Dodds (710), and Swift (’14) have 
all contributed to the early history of the germ cells in different 
vertebrates. Embryologists and histologists have contributed 
to the further history of the germ cells up to the time in which 
they become definitely placed in the fully developed germ 
glands. 
The second line of investigation has been cytological. The 
problems of spermatogenesis—synapsis, chromosome number, 
the reduction process, nuclear and cytoplasmic inclusions, ete.— 
have so occupied the attention of the cytologist that he has 
confined his study mainly to the testis of the sexually mature 
animal or to those stages in the history of the testis which fur- 
nished satisfactory cytological material. 
Among the vertebrates are some forms which have lent them- 
selves admirably to the investigation of the origin of the germ 
cells and to cytological studies. Other animals, because of their 
small germ cells or the difficulty of obtaining complete embry- 
ological series have been abandoned by both the embryologist 
and the cytologist. Eigenmann and Dodds have given excellent 
accounts of the germ cells and their behavior in the embryos of 
teleosts. Many other papers have dealt with the fertilization 
and cleavage of the teleostean egg and the embryology in a num- 
ber of teleosts has been described in detail. There is a dearth 
of literature, however, on the morphology of the adult teleostean 
testis and the germ cells in the adult have been investigated but 
little. 
It is a familiar fact that the ovaries and testes of teleosts as 
well as those of amphibians and of some other vertebrates differ 
in size at different seasons of the year. Advantage has been 
taken of the volumetric variation in the ovary of the fish to 
work out some valuable data concerning the growth and dis- 
