C. L. Walton 
From this evidence one must conclude that frost can hardly be 
regarded as an adverse factor in the life history of this snail. 
Oviposition. 
Neither in the field nor in the Laboratory was L. truncatula ever 
observed in copula although carefully watched. Braun proved 
L. auricularia to be self-fertile and this may be true of other members 
of the genus. L. peregra on the contrary may be most readily observed 
to pair; the snails indeed (as has already been recorded for this species) 
being frequently seen to form chains of three or more. Jeffreys 1 
states of truncatula “It deposits its spawn on the mud, and not like its 
congeners on the stalks and underneath the leaves of water plants.” 
In my experience in this Area the ova masses are deposited either upon 
the mud, or on stones, leaves, twigs, etc. It is impossible to be dogmatic 
without having, examined a very large number of cases, but it is my 
experience gained from a considerable number of examples, that one 
or other of these methods predominates, and it is largely governed by 
the condition of the spot inhabited. Should the flow of water be 
relatively swift and stones occur among the mud, ova will be deposited 
upon these, especially those that project above the mud, or, upon the 
top of such as may be level with the surface. 
If the flow be slight and many leaves and twigs lie upon the mud 
these will be utilised (usually the under side of the leaf), but when the 
bottom is muddy, the flow slight, and fragments few, the ova are 
deposited upon it. Leaves may decay and fall to pieces after ova have 
been deposited upon them, thus leaving the ova masses free. 
Each snail deposits several ova masses, there being from two to ten ova 
in each; seven to nine being the normal in my experience. Probably 
more are contained in the ova masses of the larger individuals (16 mm. 
in length is the largest specimen obtained in the Aberystwyth Area, 
but specimens over 10 mm. are exceptional) but I have chiefly dealt 
with smaller and younger snails, the majority of large adults being 
killed by summer droughts in 1915-16. The number of ova in a batch 
becomes less at the end of the period of oviposition when small lots 
of one to three ova are often deposited. The masses are irregularly 
rounded in form and are usually 3 to 5 mm. in diameter, and 2 to 3 mm. 
in height. They are clear and gelatinous, but generally become covered 
with particles of mud, diatoms, etc. 
1 British Conchology, Vol. i. 
