AND THE LOWER ANIMALS. 153 



it secretes, spreads out in the form of a wide disk, 

 and connects it firmly to its future home.* 



The young Aurelia changes its form and mode of 

 life simultaneously. It becomes elongated rapidly ; 

 its foot- stalk is narrowed, and its free extremity 

 assumes a club-like form. An opening soon presents 

 itself in the centre of this extremity, and exhibits an 

 internal cavity; four small projections or papillee 

 appear upon its border, and in process of growth are 

 converted into as many tentacles ; and gradually 

 others appear also, and are completed in their turn. 

 In fact, the infusorian is transformed into a polyp ; and 

 it is this which Saars first described under the name 

 of Scyphistoma. 



In its polypoid condition the Medusa exhibits all 

 the characters and properties of the real polyps. It 

 is propagated both by buds and stolons.^ Occasionally 

 the buds produced upon a portion of the body soon 

 reproduce individuals like the parent ; in other in- 

 stances they give rise to a slender stem, which trails 

 along the ground for a certain distance and develops 

 little tubercles, which in their turn will become scy- 

 phistom93, all resembling as many short, wide-mouthed 

 trumpets, whose borders are furnished with from 

 twenty to thirty slender moveable filaments. Each of 



* I have merely given Saars's opinion ; but it is more probable 

 that this quasi-mueus is a true sarcodic expansion, analogous to 

 those observed in the development of many other inferior animals, 

 even of sponges. 



t Stolons or shoots are terms applied to those slender branches- 

 of a plant, which starting from the bottom of the stem, grow out 

 laterally to some distance and then taking root produce a new 

 individual. The strawberry plant affords a very familiar instance 

 of this mode of multiplication. 



