BRITISH STALK-EYED CRUSTACEA. 137 
feed. This was a great relief to them after living for sixteen days 
deprived of all green food. 
This long period of twenty days of hard frost and sixteen days 
of deep snow, coming so soon after the hard winters of 1878-79 
and 1879-80, must have had a most disastrous effect on our small 
birds, and more especially on those species whose numbers had 
not recovered the previous losses; while the berry-eating birds, 
such as Missel Thrushes, Fieldfares, Redwings, &c., must have 
suffered considerably, for a poor supply of haws was all cleared 
off by the middle of November. 
moTEs AND. OBSERVATIONS _ON. .BRLTISH 
STALK-EYED CRUSTACEA. 
By Joun T. Carrineton, F.L.S., anp Epwarp Loverr. 
(Continued from p. 101.) 
II. SrrucruRe. 
CoNnTINUING our remarks, we now propose to give, for the 
benefit of intending students, a short outline of the general 
features which characterise the structure of this class of animals, 
more particularly with a view to affording some explanation as to 
the technical terms, which we may find it necessary to use, in 
describing or referring to the various species under consideration. 
We have already referred to Professor Huxley’s able work, ‘The 
Crayfish,’ which we have adopted as a guide in following the broad 
lines of structure, and to which we would again refer the student 
in his study of form and development of Crustacea. 
The chief feature of this class is that they possess an external 
skeleton, which is known as the EXOSKELETON. This, being com- 
posed principally of carbonate of lime with a comparatively small 
proportion of phosphate of lime, is naturally rigid, and not 
expansive or contractile; hence the necessity for a frequent 
easting of the shell which is such a prominent feature in the 
economy of these animals. It is well known that when the 
growth of the animal has so far advanced that a fresh shell or 
case is necessary for its comfort and further development, there 
takes place what is termed “exuviation” or “ecdysis”; that is, the 
old shell is entirely cast off, even to the covering of the eyes and 
z= 
