CHIROCEPHALUS. 41 



considerable accuracy the peculiar apparatus attached to 

 the head, which he considered part of the mouth. He 

 carefully watched also the process of hatching the young 

 from the egg, and was the lirst to characterise and figure 

 some of the changes they undergo before reaching ma- 

 turity. He calls it by the Linnean name. Cancer stagnalis, 

 and confounds it with the animal described by SchoefFer. 

 This confusion is kept up byBosc and Latreille, who take 

 the details almost literally as given by SchoefFer, but who 

 quote the descriptions of King and Shaw, as synonyms for 

 the same species as mentioned by him. Similar confusion 

 pervades the writings of all authors upon this subject till 

 the time when M. Benedict Prevost published an excel- 

 lent paper upon the genus, in the ' Journal de Physique' 

 for 1803, giving a very minute anatomical description of 

 the animal, with a great many details concerning its habits 

 and development, from the egg to maturity. This paper 

 having attracted the attention of M. Jurine, of Geneva, 

 then busily engaged in studying the Entomostraca of that 

 neighbourhood, he wrote to M. Prevost, requesting him 

 to send some of the ova of the little creatm'e he had de- 

 scribed so particularly. His request was immediately 

 complied with, and M. Prevost sent from Montauban to 

 Geneva a quantity of ova, wq-apped up in moist paper. 

 These, though they were four days on the road, M. Jurine 

 with great care hatched, and succeeded in bringing them 

 to maturity. Having submitted the animals so reared to 

 frequent examinations and careful study, he was enabled 

 to verify all M. Provost's facts and observations, while his 

 accomplished daughter, Mademoiselle Jurine, faithfully 

 portrayed them, as seen by the microscope. These 

 drawings having been placed at the disposal of Prevost, 

 and his original paper having received from his own hands 

 some emendations and corrections, were all published, in 

 1820, at the end of M. Jurine's work on the ' Monocles 

 qui se trouvent a Geneve ;' and the information given is so 

 full and precise, that little has been left to be added to the 

 history of this curious animal. He does not attempt, 



