54 
SHELL GALLERY. 
POLYZOA. 
Upright 
Table- 
A and B, 
at south 
end of 
Shell 
Gallery. 
(*) An asterisk against names of species denotes that specimens of these species 
are in the upright part of Case A and preserved in spirit. 
From a casual glance at the contents of these cases, it might be 
supposed that many of the specimens exhibited therein were sea- 
weeds ; but a closer inspection, especially with a lens, will reveal 
structure of a kind not to be found in any plant. 
Let us select for examination Flustra foliacea, the Broad-leaved 
Hornwrack or Sea-Mat (Fig. 1), (Case A 1), commonly to be found 
Fig. ]. 
Flustra foliacea. A, natural size ; B', portion magnified in B ; 
B, magnified 30 diameters. 
a, avicularium ; o, ovicell. 
[' The Cambridge Natural History.'] 
among heaps of sea- weed cast up on sandy shores round our 
coasts. 
The brown horny fronds, which vary in width, branch upwards 
from a narrow flat stem attached at its base to stones and shells. 
Both surfaces of the fronds show a fine network pattern formed by 
