96 THE FLAXEN FLUSTRA. 



prevented separating beyond a certain distance, by 

 a membrane of excessive tenuity, which surrounds 

 and connects the whole. This mode of the termi- 

 nation of a cell is one of constant occurrence, and is 

 evidently a provision for allowing of the freest 

 possible motion of the upper part of the body in its 

 expanded state, to which, at the same time, it affords 

 support and protection. 



The aperture of the cells in the Flustra foliacea 

 is formed by a semicircular lid, convex externally, 

 and concave internally, which folds down when the 

 polyp is about to advance from the cell. The 

 opening of this lid in the Flustra truncata, where 

 it is very long, appears, Dr. Grant tells us, when 

 seen through the microscope, like the opening of a 

 snake's jaws, and the organs by which this motion 

 is effected are not perceptible. The lid of the cells 

 opens and shuts in flustrce, without the slightest 

 perceptible synchronous motion of the polyps. 



Hooke, in his Micrographics says : " For 

 curiosity and beauty, I have not among all the plants 

 or vegetables I have yet observed, seen any one 

 comparable with this seaweed," referring to the 

 Flustra foliacea. When recent it exhales a pleasant 

 scent. Pallas compares it to that of the orange ; 

 Dr. Grant, to the perfume of violets ; and a friend 

 of Dr. Johnstone's, to the mingled odour of roses 

 and geraniums. 



In the vesicle of the Flustra carbacea, there is 

 but one egg, and as it enlarges it rises higher, till, in 



