440 
Second Report of Experiments of the 
strengthened by the discovery of a peculiar species of cercaria 
in this snail, taken from a boggy place in one of the infected 
fields, a field in which I had myself seen a badly fluked sheep 
that summer, as I can testify from the examination of its liver. 
The habits, also, of L. truncatulus render it open to suspicion, 
as it, even more than Limnceus peregcr, often leaves the water 
and crawls up the stems of water-plants and amongst the 
grass, &c., on the margins of ditches, and thus is liable to be 
eaten by stock feeding near the water. It may be found in 
very small quantities of water, such as slightly boggy spots in 
the centre of a field. But I was unfortunately unable to obtain 
specimens of L. truncatulus last summer, the localities near 
Oxford in which I had formerly found it were searched in 
vain. I went out repeatedly in quest of this snail, having on 
several occasions the skilled assistance of my friend and 
colleague Mr. W. Hatchett-Jackson, but we never found any 
other trace of this species than the empty shells. It could not 
be discovered in the localities given for it by Whiteaves in his 
paper on the Mollusca inhabiting the neighbourhood of Oxford.* 
My friends at a distance were appealed to, but were unable to 
assist me. The comparative freedom from rot of sheep in the 
neighbourhood of Oxford last year may be due to the real 
scarcity of this snail. This year, however, there were floods in 
July, and the waters of the Isis brought it down in vast multi- 
tudes ; most of the examples were small, less than a quarter of 
an inch in length. So numerous was it, that a single sweep 
of a small hand-net repeatedly gave me more than 500 examples, 
and this was in a ditch where last year I could not obtain 
a single L. truncatulus. All along the margins of the ditches 
the ground was covered with them, and they were found abun- 
dantly on the flooded ground when the flood-waters had retired. 
A favourite position is on the under-surface of the blades of 
grass, not far from the damp roots, so that sheep grazing on 
such ground would inevitably eat large numbers of them, and 
as the size is small (the commonest variety only reaches the 
length of ^ in. to | in.), and the shell delicate, they would 
scarcely attract the notice of the sheep. 
On returning three weeks later to the ditch where L. trunca- 
tulus had been found peculiarly abundant I was unable to find a 
single example alive. As I had not sufficient leisure on this 
visit to examine the ground near the ditch, I returned for the 
purpose of doing so eight days later. There had been dry 
weather since the flood, but early that morning heavy rain had 
fallen. I found specimens of L. truncatulus out on the gravel 
* ProL'Ccdiugs of the Ashiuoloau fc?ociety. 1857. 
