LYNCEID^. 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 Daphniadae, 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 Lemnge and Confervse 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 proHfic as the Daphnia3, as they pro- 

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

 the exception of \k\s,EuT>jccrcus lamdlatiis, which has nearly 

 as many as the Baphiia vetida, and is about the same 

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

 Daphniada3, the intervention of the male more than once 

 not being necessary for fecundating the eggs of the female. 

 In one species, the Chydorus spliaricus, Jurine obtained, 

 by isolating the young successively, fifteen generations ; 

 and in the Alona quadra)i(jHlaris,-\ he followed up the 

 moultings and generations for iiine successive periods. 

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

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

 got two eggs of a clear brown colour; 11th, 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. tie la Soc. Entomol.,' February 1S37, p. U, 

 M. Audouiu connnunicated the fact of his having had several sjaecimcns 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, t am 

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

 time ; but perhaps the species described by me as Fleuroxia hamatus may 

 prove to be the male of an allied species. 



f Momadm stnatm, Juriiio. 



