128 VARIETY OF LEPRALIzE. 



white, scaly crusts, altogether devoid of interest. What 

 the parasitic fungi are to larger vegetables, these little 

 animals are to their more showy neighbours. But even 

 in the humblest kinds, it is astonishing what a variety 

 of beautiful structures are met with. The common 

 observer may pass over the species of Lepralia without 

 discrimination, as being merely rude scurfs, deforming 

 the sea-weeds or shells over which they spread ; but, if 



PECISS OP LEPHALLE, MAOSIFIE 



he carefully examine them, nearly forty kinds, distin- 

 guished by very curious and elegant varieties of form, 

 will reward his labour. The polypidom in this genus 

 consists of a single layer of cells, adhering by their 

 under surface to rocks, shells, or sea-weeds, and dis- 

 posed in regular order in a more or less perfectly cir- 

 cular manner, formed row beyond row, in concentric 

 layers. Some of the more curious forms of the cells 

 are represented magnified in our figure. 



Several of the Polyzoa, especially those of the family 

 called Eschar idee, have appendages to their cells of a 

 very singular nature, the use of which has not yet been 

 determined. These odd-looking organs are attached to 

 the outer side of the cell, and resemble in form the head 

 of a bird furnished with a bill which can open and 



