278 MR. C. REID ON THE NATURAL HISTORY OF ISOLATED PONDS. 
a species likely to be brought to the locality by carts or on the 
hoofs of horses. I took home a small quantity of the ZannicheUia , 
after shaking it well to get rid of the snails, but found afterwards 
that I had brought away, adhering to it, fully 150 specimens of 
Planorbis and Limncea, mostly very minute, and several clusters 
of eggs. 
These few detailed notes will give some idea as to the general 
character of the observations ; it now remains to deal with the 
question of the relative abundance of the different species noticed 
in isolated ponds, and with the probable method by which they 
are transported. For a study of such questions it will be most 
convenient to take the species in order, beginning with the 
highest ; but it may be observed that forms of constant recurrence 
have seldom been noted, except when associated with rarer forms, 
and exact statistics cannot be given of the more abundant species. 
Amphibia are not nearly so common as one would expect, being 
mainly confined to the low-lying ponds which are within an easy 
night march from the next water across the dewy grass. Under 
such circumstances plenty of frogs and newts are to be found in 
isolated ponds, but I have only one record of newts observed in 
a dew-pond on the Downs. In this case they were seen in a pond 
near the Lewes Eace Course, about 400 feet above the sea, but 
I could not obtain specimens to observe the species. The rarity of 
Amphibia in dew-ponds may, however, be mainly due to the 
circumstances that there is seldom any shade over these ponds, and 
that there is very little mud at the bottom in which the animals 
could bury themselves. Uncongenial conditions have probably 
as much to do with the poverty of the fauna and flora in dew- 
ponds as want of transport. 
Of Fish the only species yet observed has been the Stickleback, 
which occurs not uncommonly in ponds in old brickyards and 
gravel-pits, but has only once been seen in a dew-pond on the 
Downs. The nest of he Stickleback is attached to water plants, 
and would be liable to transport with the plants. The Eel I have 
not come across, but may easily have overlooked, though, like 
the Amphibia, it is probably confined to low-lying ponds not far 
from other water. I found Eels in a pond in the large ballast- 
pit near Chichester Station, but the navvies tell me that some years 
