1912-13.] Pseudo-hermaphrodite Examples of Daphnia, pulex. 313 
The anterior margin of the right valve of the carapace is prolonged into 
a blunt process on which, and on the neighbouring ventral edge of the 
carapace, a fringe of plumose hairs is present. The process is not as large 
as that of a male, and its hairs are not so closely set (cf. figs. 5 and 6). 
The left antennule corresponds exactly with that of a typical female, 
but on the right side, arising from a deep pit on the side of the rostrum, 
there is an antennule of very different form (fig. 7). The basal portion of 
this right antennule is almost pear-shaped, its broad, proximal end is lodged 
in the pit above mentioned, and the appearances suggest that some move- 
ment of the antennule was possible. Attached to the narrow end of the 
basal segment is a flagellum similar to, but larger than, that of the male 
antennule (cf figs. 4 and 7). The length of the antennule, from its base to 
F. , flagellum ; O.F., olfactory filaments ; R., rostrum ; S. , seta. 
the tip of the flagellum, is ’33 mm. Near the ventral margin of its right 
side, this antennule bears a small elevation, from the flat summit of which 
arise seven olfactory filaments. This elevation is about the same width at its 
base as the antennule of a female (see fig. 3), but is not quite the same shape. 
The first and second trunk-limbs of both sides, when dissected free, 
prove to be identical in form with those of a normal female. The processes 
on the dorsal side of the abdomen are imperfectly preserved, hut they have 
the same general form as those of females. 
The gonads are ovaries, containing the usual oil-globules. 
Analysis of the characters of this specimen shows that, though un- 
doubtedly a female, it exhibits on the right side two of the male secondary 
sexual characters, viz. (1) the process and hairs on the anterior margin 
of the carapace, and (2) an antennular flagellum of similar form to, but 
larger than, that of a male. The basal part of the abnormal antennule does 
