LYNCEIDiE. 
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 setae, and 
have the same functions and uses. 
These insects are found in stagnant waters and slow- 
running streams, amongst the Lemnae and Confervae 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 Daphniae, as they pro- 
duce only a few eggs at a time, generally two or three, with 
the exception of th zEurycercus lamellatus, which has nearly 
as many as the Baphnia vetula , and is about the same 
size. Their mode of reproduction is the same as in the 
Daphniadae, the intervention of the male more than once 
not being necessary for fecundating the eggs of the female. 
In one species, the Chydorus sphcericus , Jurine obtained, 
by isolating the young successively, fifteen generations ; 
and in the Alona quadrangular is, f he followed up the 
moultings and generations for nine successive periods. 
On the 7th of June he isolated a female, which had eggs ; 
8 th June, two young ones born; 9 th, 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. de la Soc. Entomol./ February 1837, p. 11, 
M. Audouin communicated the fact of his having had several specimens of a 
species of Lynceus from the neighbourhood of Warsaw, sent to him by the 
celebrated Waga, and that he had ascertained tlie 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 hamatus may 
prove to be the male of an allied species. 
f Monoculus striatus, J urine. 
