STUDIES ON THE TURBELLARIA. 44:7 
in all probability, the eggs pass out through the antrum 
femininum. 
Like the testes the ovaries (fig. 2, ov.) are devoid of any 
investment. Each simply consists of a number of cells which 
extend on a more ventrally-situated plane than that on which 
the testes lie, from near the anterior end of the body to the 
neighbourhood of the oviducts. There is no differentiation of 
vitellogen cells or shell-gland cells. The most anteriorly- 
placed cells are the smallest, and their size gradually increases 
as we pass backwards until we reach the ripe ova. ‘The nuclei 
of all the unmatured cells are of the same character. In the 
larger ova they are ‘(05 mm.in diameter. There is a loose 
chromatin network and a large nucleolus, ‘02 mm. in diameter, 
within which are to be detected either one or two spherical 
bodies, having the appearance of vacuoles. The protoplasm 
of the ripe ova is very mobile, and, if it does not undergo 
active amoeboid movements, readily flows backwards and for- 
wards through the spaces in the parenchyma in which the 
ovaries are situated. Usually the full-grown ova are drawn 
out in the direction of the long axis of the body and they may 
attain a leneth of ‘4 mm. 
In the posterior part of their extent the two ovaries become 
more or less completely united behind the digestive cavity, 
and in this position during the breeding season are to be 
found a varying number (sometimes as many as eighteen) of 
completed and fertilised eggs. These (fig. 2, 00) are usually 
subspherical. With few exceptions all the many eggs 
examined were in precisely the same stage, viz. that of the 
first segmentation spindle. It would appear, therefore, that 
at this stage there is an arrest in the development, and that 
the process only goes on further when the egg is dis- 
charged. 
Maturation-stages were very rarely met with—a circum- 
stance that would seem to point to the conclusion that the 
process takes place very rapidly. In the stage immediately 
following, the female pronucleus (fig. 24) has the peculiar 
character described and figured by Gardiner in Polycherus, 
