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 wdth these Crustacea are not less numerous 

 than with the cyclops and other entoraostraca, and their man- 

 ner of living is the same. LedermuUer 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 OBSophagus, appears to have 

 more relations with the digestive functions than with those of 

 generation. 



According to Jurine, the antennte 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. 



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