ENEMIES OF MOLLUSCA — BIRDS. 
417 
Fielfl-]Mice also consume large quantities of inollusea, breaking into 
the shell by gnawing away tbe side of the whorl, and from the ascer- 
tained extent of their depredations and those of their congeners, the 
devastations of the mice must he a decided check upon molluscau 
increase. Included amongst the list of species preyed uj)on by these 
animals ai’e Heli.r cantiana, H. <irhustorum, H. asperm, II. ruft'Scenif, 
H. hispida, H. nemoral/s, H. hortensh, IlyaVmhi celhiria, etc. 
Mr. C. E. Wright detected a run of these creatures, about ten yards 
long, beneath the thick grass 
and nettles in a quarry near 
Lincoln, along the whole length 
of which broken shells were so 
thickly strewn that in the space 
of twelve inches he counted dis- 
tinct remains of ninety-six shells 
of Helix nemoralis and II. hor- 
temb, besides those of a number 
of smaller species, which would give a total of about three thousand 
shells in this restricted area. So eager and acute are mice in the 
pursuit of their prey that during winter they have been known to 
burrow into the thick snow to gain access to the hybernating IIeUce.< 
of whose presence beneath they were apparently aware ; while the 
Water Shrew dives beneath the surface to secure Lunnmi auricular ia 
and Planorhis corneus for food. 
Otters and rats have also been recorded as preying upon freshwater 
mollusks, breaking away the ventral margin of the valves of the 
Anodonta-, etc., with their teeth to gain ready access to the animal 
inhabitant. 
The Hedgehog has been deemed by many observers to be one of the 
most persistent enemies of land shells, while the Fox is accused of 
regaling himself in winter upon them when more substantial food is 
difficult to obtain. Rabbits are also accused of occasionally devour- 
ing Helix aspersa and other of the larger species, and justly so, judging 
by the number of gnawed empty shells strewn about their burrows 
and the absence of traces of any other animal likely to cause the 
destruction amongst them. 
Birds are especially destructive to molluscau life, the insectivorous 
species making mollusks a staple article of their diet during the winter 
months. The Tlinrsh tribe at all times, but especially in winter, feed 
Fig. 729. Fig. 730. 
Fig. 729, Helix aspersa Miill., and Fig. 730, 
Helix fienioralis L., illustrating the manner in 
which they are destroyed by Field-Mice. 
Collected by Mr. C. E. Wright in an ironstone 
quarry at Lincoln. 
15/12/1900 
C2 
