LYNCEID/E. 121 



valves. The other feet, from their extreme delicacy of 

 structure and transparency, are difficult to be made out ; 

 but they closely resemble those of the Daphniadse, con- 

 sisting of branchial plates and finely plumose setse, and 

 have the same functions and uses. 



These insects are found in stagnant waters and slow- 

 running streams, amongst the Lemnae and Con fervae which 

 collect in those situations. The males have not been met 

 with or described, though two, three, and even four may 

 often be seen fixed to each other, and swimming about in 

 that state.* Several species are very abundant through- 

 out the spring, summer, and autumn, and may be met 

 with in almost every pond and ditch. They are not, indi- 

 vidually, however, so prolific as the Daphnise, as they pro- 

 duce only a few eggs at a time, generally two or three, with 

 the exception of \k&Eur ycercus laiucUatus, which has nearly 

 as many as the Daphnia vetula, and is about the same 

 size. Their mode of reproduction is the same as in the 

 Daphniada?, the intervention of the male more than once 

 not being necessary for fecundating the eggs of the female. 

 In one species, the Chi/dor us splttericus, Jurine obtained, 

 by isolating the young successively, fifteen generations ; 

 and in the Alona quadrangula,ris,\ he followed up the 

 moultings and generations for nine successive periods. 

 On the 7th of June he isolated a female, which had eggs ; 

 8th June, two young ones born ; 9th, it has moulted, and 

 got two eggs of a clear brown colour ; 1 1 th, eggs are 

 elongated, eye visible; 13th, a second accouchement has 

 taken place ; 14th, has moulted, and has two eggs ; 17th, 

 a third accouchement ; 19th, has moulted, and has three 



* In the Bulletin of the 'Ann. de la Soc. Entoraol.,' February 1837, p. 11, 

 M. Audouiu communicated the fact of his having had several specimens of a 

 species of Lyuceus from the neighbourhood of Warsaw, sent to him by the 

 celebrated Waga, and that he had ascertained the existence of male speci- 

 mens amongst them. He contemplated publishing a memoir on the subject, 

 but his premature death prevented the accomplishment of his object. 1 am 

 not aware of the male having ever been noticed by any author since that 

 time ; but perhaps the species described by me as Pleuroxus hamatits may 

 prove to be the male of an allied species. 



f Monoculits striatm, Jurine. 



