SEX STUDIES. XI PA 
two ducts. The organs shown in the photograph are a coiled 
oviduct and a gland which proves to be mostly a testis (fig. 28). 
Some of the tubules show spermatids and developing sperm 
(fig. 29). This organ was sectioned in eleven different regions 
and only three showed any structures other than testis tubules. 
One of these parts is shown in figure 30. This strongly resembles 
the indifferent ovary of 1426 and 1427, so we are probably justi- 
fied in calling this an ovotestis. One other portion which was 
not testicular is most remarkable in structure (fig. F). It isa 
large solid collection of smaller masses of lutear cells partly de- 
generated and containing a few yellow pigment granules (fig. G). 
There is enough of this pigment to give the mass a yellowish 
_ tinge to the naked eye. There are also nests of lutear cells 
in normal undegenerated condition between the tubules of the 
testicular portion, as shown in figure H. This organ looks as 
though it had been an ovary and was largely changed over toa 
testis. It was certainly mostly testis when the bird was killed. 
But the yellow pigment must represent either discharged or 
atretic egg follicles and the groups of lutear cells between the 
tubules suggest that these tubules have somewhat recently 
invaded ovarian tissue. It is especially significant that these 
groups of lutear cells lie mostly toward the surface of the gonad. 
These two birds with active sex behavior have reproductive 
organs in a less active condition than 1426, with absolutely 
indifferent behavior. In fact, 1426 has mature sperm in the 
testes, while 1349 has either immature or degenerate sperm, 
and Atwood’s bird had cells ‘no further developed than the 
synizesis stage. On the female side, the oviduct of 1426 is much 
larger and more coiled than that of either of the other two 
birds, but they all have signs of having had active ovaries,— 
that is, they have several degenerating oocytes, many immature 
lutear cells, and several lutear pigment masses. No. 1426 has 
less of the ovarian tissue remnants, just as it has a more ad- 
vanced testicular structure. There are a few interstitial cells 
in 1426, but none in either of the active birds, so that active 
sex behavior can scarcely be based on these. Also the differ- 
‘ ences cannot be laid to the lutear cells, as they are present in 
all three. 
