220 APPENDIX. 



of one of these " birds' heads," and fig. 7 c, its position 

 on the cell. 



Flustra lineata. pi I. fig. 1. 



In Flustrse, the cells are placed side by side on an 

 expanded membrane. Fig. 1 represents the general 

 appearance of a species which at least resembles 

 F. lineata as figured in Johnston's work. It is spread 

 upon a Fucus. Fig. a is an enlarged view of the 

 cells. 



Flustea foliacea. pi I. fig. 2. 



We figure a frond or two of the common species, 

 which has cells on both sides. It is rarely that the 

 polypes can be seen in a state of expansion. 



Serialaria Lendigera. pi I. fig. 10. 



NoTAMiA Burs ARIA. PL I. fig. 11. 



The "tobacco-pipe" appendages, fig. 11 h, are of 

 unknown use: they are probably analogous to the 

 birds' heads in the Cellularise. 



