2296 THE ZOOLOGIST. 
strongly bending its tail inwardly towards its head. In a few minutes the 
whole of the tail or abdomen is outside of the old shell, and the two may 
be seen side by side. Then the exuviation of the front half of the lobster 
goes on, all at once, legs and head-appendages and body together, and the 
last portions but one seen of the creature in its fresh covering are the tips 
of the large anterior limbs, which, as I have said before, are for a few 
minutes a little misshapen. Last of all appear the longer tentacles. 
During this process, which from first to last takes up about a quarter of 
an hour, the lower edges of the cephalo-thorax become a little separated 
from each other, laterally, to the extent of about one inch in a large 
specimen, aud this appears to be for the purpose of allowing more room 
below than would otherwise be possible for the extrication of the limbs. 
To this end, therefore, and in my opinion for no other, does the straight 
longitudinal furrow, and its membrane below, constitute a kind of hinge 
or joint. As soon as the old shell is quite detached, and the animal is in 
its normal position, and has rested for a few minutes, it pushes the cast 
shell over the edge of the earthwork of sand and shingle, outside the den. 
Sometimes the lobster buries its old coat; but in any case this rough usage 
of it has a tendency to break the very tender membrane at the hinge, and 
usually it is found torn, and the cephalo-thorax in two. But when an 
observer, quickly after exuviation, very carefully removes it out of the 
water, it will be found quite whole, and if the shell be immediately set-up 
on a board it may dry without separation; but usually even then it begins 
to split, unless such splitting be arrested by gumming narrow strips of thin 
paper outside, across the joint, at intervals. However, I think I have said 
enough to show that no part whatever of the lobster is necessarily ruptured, 
save the membrane transversely where the cephalo-thorax and abdomen 
join, and that absolutely the whole of the interior animal comes out through 
the orifice thus formed; also that no breakage or splitting of the shell 
occurs anywhere else, the longitudinal split of the upper fore-part of the 
shell being merely an after-accident. After solidification, in three or four 
days, or within one week, the shell or animal never increases till the next 
exuyiation.” 
TrurrLes.—Most people are familiar with the appearance and taste of 
truffles, but few probably know anything about their organisation and 
reproduction. The subject is a very curious one; and although more 
suited perhaps to a botanical journal, it may be discussed not inappropriately 
in a magazine of Natural History. A French writer says (‘ Revue Encycl.’ 
xxxy. 794):—* The truffle, Tuber cibarium, is a vegetable entirely destitute 
of leafy appendages and of roots; it is nothing more than a rounded 
subterraneous mass, absorbing nourishment upon every point of its surface, 
