Marvels of the Universe 



537 



I 'koto btf'] 



'est, L.D.S. 



OBELIA. 



A small portion of the colony magnified about twenty times 

 to show the character of the cells and the polyps. 



upper surface, and has therefore failed to increase 

 ■with the growth of the fish and become merely a 

 rudimentary limb. 



SEA-FIRS 



BY EDWARD STEP, F.L.S. 



The occasional visitor to the seaside who is 

 attracted by the beauty of the smaller seaweeds 

 that he finds thrown up by the waves, and is 

 induced thereby to make a small collection of 

 them, is sure to get among them some plant-like 

 specimens that are not seaweeds at all. If, after 

 cleaning, separating and mounting them, he shows 

 them to a more learned friend, he is astonished 

 to be told that these branching growths are really 

 of an animal nature. Then he discovers that, 

 more or less thread-like though they be, they are 

 of harder, more horny character than most sea- 

 weeds. Often, when on the seashore, a tiny tuft 

 of one of these objects may be washed up whilst 

 still attached to an empty shell. If this be 

 dropped into a glass of sea-water and allowed to 

 rest for a time, its true nature will be evident. These creatures are known in the mass by the 

 popular name of Corallines — a vague term, for several stony-coated seaweeds are included under 

 it — and one of the commonest of them is known 

 as the Sea-Fir, because its stems bear some re- 

 semblance to the branch of a fir-tree. But most 

 of them, being separately unknown to the public, 

 have no English name by which to designate them, 

 which makes it rather difficult to enter upon a 

 popular account of them. Instead of using the 

 scientific name by which they are known to 

 naturalists, we have therefore used this term Sea- 

 Firs to cover the whole group. 



Returning to our glass of sea-water, we shall 

 now find that the branching colony of small 

 animals has recovered from the shock of being 

 rolled over by the waves. We find that both 

 stems and branches are deeply notched along both 

 edges, but in parts of the colony the notches are 

 filled with broad crystal vases, whose edges are 

 divided into fringes of waving tentacles. We 

 now find that our Sea-Fir is a colony of tiny cells, 

 in each of which lives a transparent animal, com- 

 parable to the Freshwater Hydra described in 

 earlier pages of this work. As a matter of fact, 

 the animals of the Sea-Fir colony and the Fresh- 

 water Hydra are not very distantly related, though 



I'lioto 6tf] 



M',.s(, L.D.fi. 



OBELIA. 



A single polyp from a colony such as is shown in 

 another photo. It has now beconrie a little jelly-fish, and 

 is here viewed from the underside. (Magnified about twenty 

 times.) 



38 



