HAY] HERMAPHRODITISM IN CRAYFISHES 225 
From the evidence now before me I would say that undoubtedly 
a partial hermaphroditism as indicated by the two sets of ducts 
described by Loénnberg or a more complete hermaphroditism as 
shown by the two sets of genital orifices in P. varicosus is the 
normal condition in the species P. brasiliensis, P. pilimanus, P. 
hassleri, P. defossus, P. saffordi and P. varicosus, while contrasted 
to this group is P. agassizi which, so far as the dissection of one 
specimen will prove, does not possess more than a single pair of 
genital orifices or tubes. 
In the genus Cambarus four specimens, two of C. propinquius 
sanbormi, one of C. diogenes and one of C. propinquus have been 
described by Faxon? as showing to a greater or less degree a com- 
bination of sexual characters. 
In the first specimen, C. propinquus sanborni, 60 mm. long, all 
the characters were those of the female, but the external openings 
of the generative organs were situated as in the male sex, upon a 
small papilla on the basal joint of each of the fifth pair of legs. 
The second specimen, belonging to the same species, 38 mm. long, 
was likewise a female in every way except that the first pair of 
abdominal appendages were like those of the male. The third 
specimen, C. diogenes, 84 mm. long, had all the external characters 
of the female except the first abdominal appendages which were 
curiously modified so as to resemble the same parts in the males 
of the genus Astacus; they were smaller in size and lacked the two 
large, recurved hooks of the normal C. diogenes. The fourth 
specimen, C. propinquus, 72 mm. long, agreed with the female in 
every respect except that the first pair of abdominal appendages 
were partly transformed into the condition which obtains in the 
male. The transformation was greater on the left side although 
on neither had it gone far enough to produce a perfect male appen- 
dage. A dissection of the first described specimen revealed the 
presence of many large ovarian eggs and Dr. Faxon’s opinion was 
that the other three in all probability were females which had 
assumed some of the characters of the opposite sex. 
To the list commented on above it is now possible to add four 
more. In the course of the examination of the extensive series of 
crayfish collected by the U. S. Fish Commission and by myself, all 
of which have been deposited in the U. S. National Museum, I have 
found two specimens of C. spinosus, one of C. propinquus and one 
of C. affinis which show evidences of hemaphroditism. 
* Memoirs of the Museum of Comparative Zoology, x, No. 4, p. 13, 1885. 
