44 
snails, it seems the very climax of suicidal folly for them to go 
up the trees at such a critical period of their existence. 
The causes which determine the colouring of these variable 
snails are very obscure. Why should nearly all the specimens 
of hortensis up Skelton Lane be yellow, plain or handed, while 
at Dringhouses they are mostly pink ? ^Vhy still more should 
the snails which lived in that little hit of hedge near the 
footpath from St. Mary’s to the Scarhro’ Railway Bridge he a 
remarkable dark liver colour, occuring nowhere else near 
York, and alas! no longer occurring there, owing to one of 
those improvements which naturalists lament everywhere ? 
And to add insult to injury, they positively asked me to 
suhscrihe to the footpath which has destroyed the haunt of my 
precious snails. Why again should it please most of the pink 
Redcar shells to have only one hand, while at Burlington that 
is the form of ornamentation selected hy the yellow, and the pink, 
if they wear hands at all, adopt four or live? Sir John Luhhock 
is feeling his way to the laws of colour among flowers, hut the 
laws of colour among animals are at present almost entirely 
unknown to us, and though self-protection may explain the 
stripes of the jungle-haunting tiger and certainly does explain 
the colouring of many insects, thousands of instances might he 
quoted, and among them our pink and yellow snails, where 
colour rather invites than precludes observation. 
Variety of form and texture, however, may generally he 
accounted for with more or less satisfaction. Helix nemoralis 
and hortensis are widely distributed forms, occuring like all our 
other snails, over a considerable part of Europe. Therefore, 
as might he expected, they exhibit considerable variety of size 
and strength. The largest examples of these snails I have seen 
come from Yevey, on the Lake of Greneva. The warm climate 
and abundance of lime sufficiently explain their robust character. 
Specimens from San Sebastian, at the foot of the Pyrenees, are 
nearl}^ as large. In England, the finest sj)ecimens come from 
the limestone districts of the South. The tiniest examples I 
have met with come from Knareshro’, near St. Robert’s chapel. 
As the rock at this point is magnesian limestone the reason for 
their dwarfed character is obscure. They are white lipped, 
