246 
Liver Rot of Sheep 
deposit of diatomaceous mud; it dislikes the soft mud upon which 
peregra dwells and will crawl away from it, if possible. 
Food of L. truncatula and L. peregra. 
In order to ascertain the food of L. truncatula the intestinal contents 
were carefully examined at different times of the year, and were found 
to contain mud, consisting for the most part of quartz fragments, etc., 
together with residual vegetal matter. The mud amidst which the 
snail lives and feeds consists of the same particles of inorganic matter 
as were found in the intestines, together with the remains of decayed 
vegetation a number of Diatoms and occasional Desmids. 
Prof. Fleure considers that the radula form in this mollusc is well 
fitted for shovelling in this mud. 
L. peregra shows very similar intestinal contents, the only difference 
being that the organic particles are much finer, but peregra as already 
stated, prefers mud of softer and finer texture than does truncatula. 
It has been stated that grit is retained in order to act as a “grinder” 
but if the excreta of L. truncatula are examined microscopically they 
will be seen to consist largely of quartz fragments similar to those found 
in the gut. Entire frustules of Diatoms, have also been detected in 
the excreta and it is my opinion that the mud is ingested in order to 
obtain the Diatoms. Snails were washed clear of all mud and placed 
in tubes containing water only, and their excreta, as long as any were 
passed gave the same result. 
Forty samples of mud were collected from all over the Area and 
examined microscopically. Some were from streams and ditches 
devoid of either species of Limnaea, others were from spots inhabited by 
only one species, some were from clay, others from peat. 
In practically every case where L. truncatula was found Diatoms 
were common or abundant, and a few Desmids were present; where 
peregra only occurred no Desmids were recorded, but Diatoms were 
fairly common, but where neither were to be found Diatoms were small 
and few in number and species. Diatoms are abundant in peaty 
streams, etc. 
L. truncatula continues to feed throughout the year and growth 
is of course more or less continuous also, (in this Area and during the 
course of the Survey at any rate) snails collected during Dec. and 
January at 1000 feet above sea level and at water temperatures as low 
as 38° F. showed the same intestinal and excretory content and activity 
as those collected at other times. 
