EARTHWORMS.—SLUGS. 401 
Earth-worms for the most part retreat deeper 
into the ground in winter to avoid the cold, but 
though not torpid are very lethargic and inert, and 
when touched do not display their usual fear; these 
and slugs seem when disturbed, as if half awaken 
out of a profound sleep. Their torpor is not of 
that perfect kind which suffers the application of 
heat and other stimuli a long time before resuscita- 
tion is effected,—vital operations are but partially 
suspended,—the state may be termed semi-torpidity. 
Slugs mostly are semitorpid, but some few con- 
tinue active or sparingly so. Their winter habits 
seem to yary in different species, for the field slug is 
tolerably active, whilst the Limacellus unguiculus 
is laid up in decayed vegetable matter, &c. and 
admits of being squeezed between the fingers be- 
fore animation is restored. This kind moreover lays 
itself up early in October. Some sorts retire deep 
into the soil like worms, and when disturbed shew 
slight motion, some are concealed in rubbish, and 
some coutent themselves with a domicile under a 
loose stone. Intervening mild weather in winter 
probably restores all the kinds of torpid slugs as 
also the earth-worm to their usual habits of life. 
The Blackcap arrives here with tolerable regula- 
rity about the last week in April, and often earlier, 
though itis evidently retarded in its transit by un- 
usually cold or inclement and wintry weather, and 
then is not seen till the first week in May, but I do 
not say that it may not actually arrive before that 
time, and remain perhaps unobtrusive till milder and 
sunny weather invites it forth ; and yet I see by a 
catalogue of summer and winter birds of passage 
furnished me by an intelligent naturalist of Kendal 
in Westmoreland that in that neighbourhood it 
does not arrive till May 4th, besides which, Ll am 
certainly of opinion that birds intuitively put off 
their migration on the occurrence of unusually 
Zz 
