302 
BRITISH ENTOMOSTRACA. 
which represent so many articulations, but no trace of 
which is visible on the under surface. These articulations 
are comparatively small, with the exception of the fourth, 
which composes the enormous lateral expansion, these, in 
fact, being nothing more nor less than an excessive de- 
velopment of this division of the body. The last joint is 
much smaller than this, but is considerably larger than 
those which precede it. 
The first four segments give off an equal number of 
pairs of feet, and the fifth gives attachment to a rudimen- 
tary pair, similar in structure to those described in the 
Cyclopidse as the fulcra or supports of the ovaries. The 
extraordinary enlarged lateral bags, or expansions, com- 
posing the fourth ring, inclose the intestines, and as 
Latreille first suggested, in all probability contain a bran- 
chial apparatus, similar to that described in the large 
carapace of the Apus. The chief part of its contents, 
however, according to Rathke, who has paid such par- 
ticular attention to this little animal, is the internal ovary. 
In fact, according to this author, “ these appendages are 
originated by the female organs of generation, which, as 
they considerably increase in volume, cause the sides of 
the body to project right and left, like a sac. In each of 
these lie two organs, differing in size and colour, which 
may easily be recognised through the integuments, as they 
shine through them very distinctly. The larger organ is 
of a rose or crimson colour, and appears, under a low 
microscopic power, to consist of a pulpy mass. Under a 
higher power, we become aware that it is formed of an 
infinite number of roundish, rose-coloured eggs, held to- 
gether by a colourless, glutinous matter, which forms, no 
doubt, the envelope of the organs. This rose-coloured 
organ, then, is the ovary. The other, and much smaller 
organ, lies under this, on the abdominal wall of the body, 
is distinguished from the former by a milk-white colour, 
and presents in general a winding, serpentine canal, of 
uniform width, which runs along almost to the further 
blunt extremity of the wing-like appendage, and from 
