PROTECTIVE RESEMBLANCES AND DEVICES. 
331 
and destruction of the more conspicuous specimens, and the pre- 
servation of those variations wliich harmonize most closely with the 
environment, while heredity will assist in the perpetuation of those 
individuals, which either by colouring, form, or habit are most 
difficult to distinguish amidst the surroundings amongst which they 
habitually live. 
Amongst exotic species many striking instances exist of the pro- 
tection afforded by resemblances to other objects, and although in 
our own more prosaic country we can scarcely hope to have examples 
of so striking and beautiful a character, they are yet of the highest 
interest and probably of vital importance to the welfare of the 
different species. 
Amongst the slugs, Mr. G. Sherriff Tye has recorded the similitude 
oi A vion hortensis and AgrioUmax agrestis to the fallen bloom sheaths 
of the Black Poplar (Fopulus nigra L.). This resemblance is affirmed 
to be sometimes so perfect that the keel, pallial line, and even the 
corrugated surface are so strikingly simulated as to render the 
deception quite complete, and Dr. Scharff and others have recorded the 
striking similarity between the animal of Geomalucm maculosus 
and the foliage of Frullania dilatata and other liverworts and lichens, 
amongst which it lives and finds its food, while other .species have 
been .shown to closely resemble other familiar and inedible objects. 
Amongst laud shells, Buliminus obscnrus has long been noted for 
an analogous habit to that of the burrowing bivalves, and its adven- 
titious protective covering does undoubtedly vary according to the 
situation inhabited. In woods where the trees are clad with lichens, 
this little shell is similarly clad and then resembles little moss-covered 
knots or excrescences upon the bark of the trees ; or, if found on dry 
hedgebanks or on roadside trees or walls it often bears a most natural 
resemblance to a misshapen piece of mud or stone. 
Protection is probably also secured by Helix fusca through its 
wonderful resemblance to the decaying capsule or seed-case of the 
Red Campion ( Lychnis diurna). This resemblance is, according to 
Mr. Masefield, so faithful as often to require a close scrutiny to 
determine whether the doubtful object be a snail or a seed pod, as 
this .species is the exact colour of the capsule when wet — a trans- 
imrent horn colour, and the bottom of the seed-case being light- 
yelloAv exactly reproduces the appearance of part of the viscera of 
the mollusk as seen through the shell. 
