Marvels of the Universe 



565 



Photo hif] 



A FERN-LIKE SEA-PEN. 



The polyps are on the upper sides of the ' barbs " on!: 



[Fuller <(■ Osborne. 



barbs are borne on the stem in one plane, just as in the case of the barbs of a feather ; whilst to add 

 to the resemblance there is a centre hard stalk, or corallum, of lime, which runs up the middle of 

 the whole organism ; and this, of course, gives it the support necessary to hold the structure together. 

 That part of the animal which answers to the business-end of a quill-pen, as one might say, is really 

 what ser^-es as a root, by which it is embedded in the sea-bed. The creature seems to love a muddy 

 or sandy bottom, and in this respect is in marked contrast to many other lowly creatures which 

 love only a clean, hard bottom. The shaft of the quill is embedded more or less loosely in the mud 

 or sand, and to that extent is not altogether immovable, but its powers of locomotion, if any, must 

 be ver\- small. The older naturalists attributed to it the power of flapping the pinncE of which each 

 barb is composed, after the manner of the fins of a fish, and so maintaining a certain amount of 

 locomotion ; but Lamarck, who, at the beginning of the nineteenth century, was engaged in his 

 zoological researches, expressed his doubt of this theory, and it has since been proved that he was 

 right, for " when placed in a basin of sea-water, the Sea-pens are observed never to change their 

 position but to remain in the same spot and lie with the same side up or down just as they have 

 been placed. They inflate the bod}' until it becomes to a considerable degree transparent and 

 only streaked with intercepted lines of red, which distend at one place and contract at another ; 

 they spread out their pinna and the polyps expand their tentacles, but they never attempt to swim 

 or perform any process of locomotion." 



Some of the Sea-pens are phosphorescent, and these present a magnificent sight in the darkness. 

 Linnseus tells us that where they occur in numbers on the bed of a sea, they cast sd strong a light 

 that the fishes and worms which sport around them can be easily counted with their aid. Many 

 of the coral-reefs owe a great part of their adornment to these graceful and brightly-coloured 

 zoophytes, growing wherever the coral sand has collected sufficiently to give them a foothold. The 



v^X*?^-.^/^',. 



Photo hu] 



THE HART'S TONGUE SEA-PEN. 



The stem is capable of expansion and contraction. 



IFuUer A- Oshnrne. 



