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 



