G uide to Crustacea. 
Wall- 
cases 
Nos. 1-i 
Fig. 6. 
Series of cast shells obtained from a single 
individual of the Shore-Crab ( Carcinus 
maenas ) kept in an aquarium. The 
carapace of the largest is about inches 
wide. [Wall-Case No. 3.] 
of the Edible Crab, of which 
one is in the act of moulting. 
The carapace has become 
separated from the abdomen 
and legs, and the body is 
beginning to be withdrawn 
from it. 
On the right of the case is 
a series of cast shells obtained 
from a single individual of the 
Shore-Crab (Eig. 6). The crab 
was captured on 14th May, 
1901. It was then in the 
second larval or Megalopa 
stage, and was found swimming 
at the surface of the sea. It 
lived in Mr. Waddington’s 
aquarium till 20th July, 1904, 
and during that period it 
moulted seventeen times. All 
the cast shells, except two which 
were destroyed by accident, are 
exhibited. 
In the lower part of the 
case two very beautiful series 
are exhibited, each obtained 
from a single Lobster in Mr. 
Waddington’s aquaria, and to- 
gether they give an almost 
complete picture of the growth 
of the animal from an early 
post-larval stage until it reaches 
a marketable size. The younger 
series begins with a specimen 
of about -fths inch length of 
body, which moulted on 21st 
August, 1906 ; the latest of the 
fourteen moults exhibited was 
obtained on 8th June, 1909, 
when the animal was about 
4£ inches in length. The second 
series begins with a specimen 
