CORALS. 407 



parent, they are tiny flask-shaped beings, covered with minute 

 cilia, by means of which they can pass through the water with 

 some rapidity. They have a kind of mouth at the small end, 

 which corresponds to the neck of the flask, and it is a curious fact 

 that they always swim with the large end forward. 



After a time they change their shape, elongating until they 

 look like little white worms, but still moving about after the same 

 fashion. They pass some time in this phase of existence, and 

 then settle down upon some fixed object, such as a rock, and ad- 

 here to it by the enlarged base. Scarcely have they done so 

 than they again alter their shape, and assume a form so different 

 that no one who was not acquainted with the little creatures 

 could recognize them. Instead of being long and worm-like, 

 they now contract themselves in length, while they proportion- 

 ately increase in width, and look something like an echinus, or 

 sea urchin. 



It is a curious fact, that up to this time they have passed 

 through four stages, and in each stage they change in length. 

 Before they issue from the parent they are nearly spherical, but 

 when they pass into the sea they assume the flask-like shape. 

 They next elongate themselves considerably, and then suddenly 

 become even shorter than their width. 



In this fourth stage the mouth is surrounded by eight little 

 cushion-like projections, which soon sprout into the beautiful 

 fringed tentacles which give to the animal so flower-like an ap- 

 pearance. 



"When it has arrived at this stage of existence, the young Coral 

 begins to develop some new and remarkable powers. From vari- 

 ous parts of the body spring little projections, which soon exhibit 

 an orifice like the mouth of the original Coral, and in a short time 

 this aperture is surrounded with cushions, which are developed 

 into tentacles as before. As soon as it comes to maturity, each 

 of these supplementary Corals puts forth similar buds, so that the 

 increase is wonderfully rapid, even by " gemmanation," as this 

 mode of multiplication is called, not to mention the vast numbers 

 of new settlements that are made by the young which are poured 

 from the mouth. 



Although we have now learned the method by which the Coral 

 animals are reproduced, we have not ascertained how the solid, 

 stony substance which we call Coral is formed, nor the precise 

 connection which exists between the animal and the Coral. 



