198 THE ENTOMOSTRACA OF EPPING FOREST.
a method probably unique among the Cladocera. I am well
aware, however, that several authors state that other species use
the "cervical gland" for attachment, but f believe this to be
erroneous. In the species of Simocephalus the clinging is accom-
plished by means of an alteration of one of the three terminal
setae of the outer or dorsal branch of each of the swimming
antennae. The tip of this seta, instead of tapering to a simple
point, is bent round into an excessively minute hook, and it is
by means of this that the animals can suspend themselves. In
the genus Scapholeberis, and in nearly all the Lynceidae, the cling-
ing is apparently brought about by the little hooked setae on the
first and second pairs of feet. These animals, therefore, in
direct contradistinction to Sida and Simocephalus, rest with the
ventral aspect of their bodies towards the supporting object.
Not only can the "clingers" among the intermittent swimmers
fix themselves to solid objects, but some of them have
also the curious habit of using the surface-film of water for
support. The two forms which do this most systematically, and
which present special adaptations for the purpose, are
Scapholeberis mucronata and Notodromas monacha, but others, such
as Cyclops fuscus and C. prasinus, may likewise be seen at times
clinging to the surface-film (S3). To the group of the inter-
mittent swimmers also belong the species of the Branchiura.
These are all externally parasitic upon fishes, and, like our
Argutus foliaceus, attach themselves to their hosts by means of
powerful suckers.
Concerning the non-swimming species of Entomostraca not
very much need be said. The group consists very largely of
Ostracoda belonging to such genera as Herpetocypris, Ilyocypris,
Caudana, and Limnicythere. To these must be added the parasitic
Copepods, of which the adult females, at least, seem never to
leave their hosts, and a few species of Cladocera all belonging
to the genus Ilyocryptus. It may be pointed out that the non-
swimmers are nearly all bottom-loving animals, though some of
the Ostracoda crawl about freely among aquatic vegetation when
they get the opportunity.
Many other miscellaneous facts connected with the habits
of the Entomostraca could easily be added if this section were
not already too long. Nevertheless nothing that has yet been
discovered in this branch of study can be considered to have
done more than just lift here and there the veil that covers a