566 



Marvels of the Universe 



possession of this attribute in a peculiar degree has given its name to one of the species which is 

 to be found in British waters. This is the Phosphorescent Sea-pen. In repose its colour is dull 

 purple-red, but when the dehcate transparent polyps are expanded and the brilliant phosphorescence 

 changes the dull hue to a deep purple it becomes an object of splendour and deserves its fame as the 

 most beautiful of British Sea-pens. 



When we come to consider the manner in which a Sea-pen is built up, we shall at once notice 

 a great similarity to the corals. The barbs are full of separate individuals, each in its own little 

 sac, from which it can protrude itself, or into which it can retract itself at will. They are, indeed, 

 little coral polyps ; but instead of being able to create masses of coral-limestone reefs, all they do 

 is to secrete from the sea- water just enough lime to form the hard, central rod, and this is almost 



the only thing the whole organism 

 has in the way of a hard skeleton. 

 In this it bears a close resemblance 

 to the precious red coral, which is 

 but a skeleton, and is covered with 

 sarcode or jelly-flesh when living, 

 and this contains the individual 

 polyps seated therein. So with the 

 Sea-pen, the central rod is hidden 

 by a layer of flesh, sometimes of 

 considerable thickness, and the barbs 

 themselves are also flesh-covered. 

 Then on the barbs are placed the 

 little polyps, differently arranged in 

 different species. These polyps rest 

 in their separate little clefts, and, 

 when living, protrude their rosettes of 

 tiny tentacles and wave them in 

 the water, endeavouring to pick up 

 the morsels of nourishment which 

 stray within their reach. They are 

 veritable sea-anemones in miniature, 

 and they alwa^'s have eight tentacles 

 surrounding their central mouth. 



The typical quill-pen arrangement 

 is departed from in some species, 

 for the barb will be found at times 

 so thick and bushy as to look like 

 a fair-sized brush, of which the handle is formed by the naked lower portion of the stem, or 

 rachis. The Phosphorescent Sea-pens of British seas, mentioned above, are of this kind, 

 and in warmer seas they may be found a foot in length. The lower stem is of a creamy 

 colour. One can well understand why this creature was long thought to belong to the vegetable 

 world. First, the stem was planted in the mud of the sea-bed. Then there was a central 

 soft stem, with a hard " pith," as one might call it. On each side of the stem small leafy 

 branches were given off, and on the upper sides of these there grew a number of rosette-like flowers 

 which we know now to be polyps surrounded by tentacles, each having the power of withdrawing 

 within the particular cleft in which it lives. This latter characteristic, however, clearly shows its 

 animal nature. Again, each polyp, though closely associated with its neighbouring polyps, is a single 

 individual with a distinct mouth and bodv, and its own series of tentacles. Many thousands of them 



[/jj, 7V,e... Carm-as. 

 A "CHALLENGER" SEA-PEN. 



A very beautiful and very intricate spe:ies. The polyps fringe the edge 

 of each one of the curled fronds. While curled in this and the following 

 illustration. Sea-pens are more or less flexible, though with a hard central 

 stalk, which inclines to the perpendicular. 



