HAY] HERMAPHRODITISM IN CRAYFISHES 227 
perforated by the opening of the sperm duct. The first abdominal 
appendage of the right side, while of the same pattern, is misshapen 
and only half as long as its fellow and the basal segment of the con- 
tiguous fifth leg is imperforate. The second abdominal appendage 
of the left side is developed as in the male while on the right side 
it is as in the female. 
A careful dissection of this specimen has been attempted but it 
has been so poorly preserved that nothing can be determined. 
There is a large mass which is probably the ovary, but there is no 
trace of a spermary or sperm ducts and even the oviduct can not 
be identified with certainty. 
The fourth specimen, C. affinis, 106 mm. long, from the Potomac 
River, near Washington, has all the external characters of a fully 
developed first form male except that on the basal segment of the 
third pair of legs there is, on each side, an orifice of an oviduct. 
These orifices are not operculate and in 
the living animal the white oviducts pro- 
truded conspicuously and first called my 
attention to the specimen. A careful 
examination shows no other female char- 
acters except that the basal segment of 
the fifth leg of the left side is not per- 
forated by a sperm duct. The first pair 
of abdominal appendages are perfectly 
formed and the third pair of legs bear 
strong hooks. The internal organs of 
this specimen show a most astonishing 
reversal of conditions. There is a large 
ovary, a little more developed on the left 
side than on the right, well filled with 
nearly mature eggs. On each side a 
perfectly formed oviduct passes down- 
ward to the bases of the third legs. On 
ieroit side a short and net muchcoileds | P16. 47-——-Dorsal view | of 
sperm duct leads upward from the base “" ne ere re 
4 ual of Cambarus affinis. 
of the fifth leg to a rudimentary spermary 
which lies directly upon the ovarian mass and is partially imbedded 
init. The diameter of the spermary is about four millimeters and its 
greatest thickness about two and a half millimeters. There is not 
the slightest trace of a spermary or sperm duct on the left side. 
A microscopic examination of the spermary and the sperm duct 
have failed to show the presence of spermatozoa but there is a 
