A REPORT ON INVESTIGATIONS IN THE DENEHOLES 9
The following categories of cave-dwellers are now generally
used, Glennie (1945): —
Trogloxenes—Occasional dwellers in the dark zone of caverns,
but not completing their whole life-cycle in caves, etc.
Trogloxenes may be habitual or accidental.
Troglophiles—Species living permanently and reproducing suc-
cessfully in the dark zone of caverns, but also to be found
living permanently outside caves or in threshold regions.
Troglobites—Species living permanently in the dark zone.
Most of the species found in the deneholes would appear to be
accidental trogloxenes, but representatives of the other categories
also appear to be present.
In May 1959 all the chambers were searched roughly, chambers
of Nos. 9 and 10 were searched closely, and the heaps of debris at
the base of shafts Nos. 3 and 5 were examined fairly closely.
Small invertebrates were abundant on the heaps of debris, and
no attempt was made to obtain a completely representative col-
lection. Generally those groups were collected, which could be
identified at the time. In chambers remote from the open shafts,
every individual seen was collected. Traps, which consisted of
jars baited with strong cheese or bacon-rind, were sunk in the
floors of various chambers, but produced no captures. In January
1962 most chambers were again roughly examined. The shaft of
No. 3 was then apparently completely blocked, but the heap of
debris beneath the shaft was closely examined, and a few speci-
mens were found. The heap of debris at the base of shaft No. 5
was completely trampled, and collecting was not worthwhile.
In May 1959 a number of snails was seen to be active at the
base of the open shafts, but none was taken. About a dozen
specimens, which were taken from the base of shaft No. 3 in
January 1962, all proved to be Oxychilus cellarius (Muller).
The four common species of woodlice (Isopoda) mentioned later
were abundant at the base of the open shafts in May 1959. Two
specimens of Oniscus asellus L. were found in a chamber of No. 5
about 30 feet from the shaft. In January 1962 no woodlice were
seen.
Two species of millipedes (Diplopoda), Polymicrodon polydes-
moides (Leach) and Brachydesmus superus Latzel, were abundant
in May 1959 at the base of both the open shafts, and a few P.
polydesmoides were found in the chambers of No. 5. About 10
millipedes taken from the base of shaft No. 3 in January 1962
proved to be P. polydesmoides. These two species, although
common outside of caves, are well-known as troglophiles, Blower
(1958). Neither of the species, however, was found more than
30 feet from the open shafts, but as P. polydesmoides, at least,
is still to be found at the base of shaft No. 3, it would seem likely
that it is the presence of food (decaying plant remains) that con-
fines this species to the base of the shafts, rather than the higher
light intensity. A single specimen of Polydesmus coriaceus