336 
CLASS CRUSTACEA. 
and conical vessels, closed at their origin, situated at the pos- 
terior parts of the body, under the testa, and open, one by the 
side of the other, at the anterior part of the abdomen, where 
the canal formed by the tail establishes a communication 
between them. The eggs are spherical. The times of laying 
and moulting with these Crustacea are not less numerous 
than with the Cyclops and other entomostraca, and their man- 
ner of living is the same. Ledermuller says he has witnessed 
their sexual intercourse. Nevertheless, none of the modern 
naturalists, who have observed them most closely, could ever 
positively discover their sexual organs, nor witness their 
union. M. Straus has seen below the origin of the mandibles, 
the insertion of a thick conical vessel, filled with a gelatinous 
substance, appearing to communicate with the oesophagus by 
a narrow canal, which he suspects to be a testicle or a salivary 
gland. The individuals subjected to this observation having 
ovaries, the cypris would be, on the first of these suppositions, 
hermaphrodite. But that is so much the more doubtful, as he 
himself remarks, that the males may very probably exist only 
at a certain time of the year, and that the vessel of which he 
speaks, communicating with the oesophagus, appears to have 
more relations with the digestive functions than with those of 
generation. 
According to J urine, the antennae are true fins, the filaments 
of which these animals develope, and re-unite at will, accord- 
ing to the degree of rapidity which they are desirous of com- 
municating to their progress. Sometimes they only allow 
a single one to appear, at others they unfold them altogether. 
We also think that these filaments, and those of the two ante- 
rior feet, may just as well concur in respiration as those 
laminae of the mandibles and of the two upper jaws, which 
M. Straus calls branchial. The last, or those of the jaws, 
appear to me to be a true palpus, but much dilated, and the 
two others an appendage of the mandibulary palpi. 
