76 EVENINGS AT THE MICROSCOPE 



table Algce, or sea- weeds. But here are other plant- like 

 objects of a pale brown, drab, or snowy-white hue. Let 

 us take this flattened brown leaf, divided into irregular 

 broad lobes; it looks almost like a thickish paper, and is 

 about as flexible. But pass your finger over it, and 

 you feel that its surface is evenly roughened; and on close 

 and careful scrutiny you discern, even by the naked eye, 

 that its surface is covered with a delicate network of mi- 

 nute shallow cells. 



"Broad Horn wrack" and "Leafy Sea-mat" are the 

 names which the old collectors gave to this object; and 

 modern naturalists have given it the scientific appellation 

 of Flustra foliacea, and arrange it in the class Polyzoa, a 

 group of animate beings which have much of the form of 

 Polypes and much of the structure of Mollusks. 



We cut off a little piece from the end of one of the lobes, 

 and put this upon the stage of the microscope. We now 

 see that the cells are disposed in nearly parallel rows; but 

 so that those of one row alternate with those of the next, 

 quincunx fashion, the middle of one cell being opposite 

 the end of its right and left neighbors or like the meshes 

 of a net. The cells extend over the whole leaf, and are 

 spread over both its surfaces in this case; the united 

 depth of two cells constituting the thickness of the leaf- 

 like structure. There are other species, more delicate, 

 which have but a single series of cells, all opening on the 

 same side of the leaf. 



Each individual cell is shaped like a child's cradle; and 

 if you will imagine 20,000 wicker cradles stuck together 

 side by side in one plane, after the quincunx pattern I 

 have just mentioned; and then the whole broad array 

 turned over, and 20,000 more glued on to these, bottom 



