THE ENTOMOSTRACA OF EPPING FOREST. 269
Connaught Water, Chingford. This well-known pond
is characterised by an almost complete freedom from aquatic
vegetation, and by the possession of a soft clayey bottom
which renders the water turbid upon very little disturbance.
The Entomostracan fauna, corresponding with these peculiari-
ties, consists mainly of two sharply divided groups—namely,
Plankton-forms and Mud-lovers. There are, of course, as
in most other ponds, a few of the universally distributed
forms also present, but they do not affect the general
character of the fauna. To the group of plankton species
belong Daphnia hyalina, Bosmina longirostris, B. cornuta, and
Cyclops viridis (brevicornis). Strangely enough Diaptomus
gracilis, which almost invariably accompanies such forms as
the foregoing, has never been taken in this pond. The
reason for this is a mystery to me. I can only suggest that
it may be connected with the frequent cloudiness of the
water. The mud-loving and bottom forms are well represented
by Macrothrix (two species), Ilyocryptus, Leydigia, AIona quad-
rangularis, A. affinis, Pteuroxus uncinatus, Cypria ophthalmica, llyo-
cypris, Limnicythere, &c. The best find from this station,
perhaps also the best from the whole district, has been Macro-
thrix hirsuticornis. Unfortunately, however, it was only seen on
one occasion, although present then in fair abundance. It seems
to have failed altogether in establishing itself. I consider it to
be very probable that the resting eggs of this species were intro-
duced by some of the wild ducks or similar birds occasionally
frequenting the pond, and that, after hatching and undergoing a
brief period of parthenogenetic development, the species found
the conditions incompatible with its further existence.
Cuckoo Pits, Chingford. The three or four little
ponds and pools occupying the hollows known as Cuckoo
Pits, are situated in a small clearing in one of the
densest parts of the Forest. They are very shallow,
almost completely choked with weeds, and, with one exception,
dry up in the hottest part of the summer. The Entomostracan
fauna of these ponds is characterised by the presence of the three
littoral Ceriodaphnias (C. megalops, C. rotunda and C. reticulata)
and absence of the semi-pelagic C. quadrangula, and by the
presence of Daphnia obtusa, Alonella excisa, and three species of
Cyclops of the " bicuspidatus " group—namely, C. bicuspidatus,
8 Perhaps from the north. The only previous British records have been Sunderland
and Shetland.