54 



SHELL GALLERY. 



Upriglit 

 Table- 



A and B, 

 at south 

 end of 

 Shell 

 Gallery. 



POLYZOA. 



(*) An asterisk against names of species denotes that specimens of tliese species 

 are in the upright part of Case A and preserved in spirit. 



Feom 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 Mustra foliacea, the Broad-leaved 

 Hornwrack or Sea-Mat (Fig. 1), (Case A 1), commonly to be found 



Fis. 1. 



Flustra foliacea. A, natural size ; B , portion magnified in B ; 



B, magnified 30 diameters. 



a, avicuiarium ; 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 



