G. FLUSTRA. 43 



cd with the animals to whose cells their habitation ad- 

 heres. There are, however, strong grounds of pre- 

 sumption that the more perfect result of observation 

 will prove them not excluded from what we deem a 

 general and characteristic distinction. When we are 

 better acquainted with the Polypidoms, we shall be 

 more at liberty to observe the Polypi ; when the atten- 

 tion is devoted to one object, its peculiarities are more 

 likely to be discovered. 



The Flustras vary much in form ; sometimes they 

 appear as simple membranes extended on the fu- 

 cus ; others rise in leafy but flat surfaces, lobed or 

 entire, sometimes in verticillated branches, the cells 

 always contiguous, hexagonal or polygonal, and have 

 their partitions perpendicular to the surface on which 

 they are established ; the upper part usually convex 

 or hemispherical, and formed of a substance more 

 membranous, thinner, and more transparent than the 

 side partitions, and which usually disappears by dry- 

 ing, sometimes so soon after the death of the animal, 

 that we are inclined to suspect it either forms part of 

 the body or adheres to it. 



When the animal of the Flustra has acquired its 

 full growth, it flings from the opening of its cell a 

 small globular body, which fixes itself near the open- 

 ing, increases in size, and soon assumes the form of 

 a new cell : it is yet closed, but through the transpa- 

 rent membrane that covers its surface, the move- 

 ments of a polypus may be perceived, who delays not 

 to burst the enclosure of his little habitation ; then, 

 exulting in the plenitude of existence, he exercises 

 its functions, and by the assistance of twelve tentacula 



