214 



Marvels of the Universe 



In the Star-fishes and Sea Urchins these tube-feet are arranged in five rows, but in the Sea 

 Cucumbers the}' are not as a rule so regularly disposed. In the latter group some of the tube-feet 

 are so placed as to take no part in locomotion, and so modified as to become mere sense organs, as 

 in the two shown on page 216 ; whilst in the one that lives at the sea-surface they are modified 

 into swimming appendages and resemble the tentacles of a Jelly-fish. In fact, in all members of 

 the familj' these tube-feet have other than locomotive uses. Romanes has shown from e.xperiment 



that even in the Star-fishes, 

 where they are situated on 

 the under side, they act as 

 the organs of smell and that 

 it is by their means that the 

 animal is enabled to find 

 its food. 



The eggs of the Sea Cu- 

 cumbers in most cases are 

 set free in the water, hatch- 

 ing and development there 

 taking place quite indepen- 

 dent of the parent ; but in 

 some the eggs are hatched 

 and the young developed 

 within special brood-pouches 

 possessed by the mother. 

 The eggs of the Saffron- 

 coloured Sea Cucumber be- 

 come attached to the back 

 of the mother, where the 

 young hatch out and remain 

 until they have attained a 

 considerable size, as shown 

 on page 215. 



The Sea Cucumbers have 

 around the mouth a circle 

 of ten tentacles, which can 

 be expanded or withdrawn. 

 In some species these are 

 small and simple ; in othei's 

 they are elegant branched 

 appendages ; whilst in others 

 they are like little fern 

 fronds, and are well shown 

 on the opposite page. 

 food is secured ; they are 



A SWIMMING 



re ha 



SEA 



Although this creature has more resemblance to 

 to be a near relation of the Sea Cucumbers such as are 

 muscular web stretches between the "arms." and by i 

 animal makes its way through the surface waters. 



CUCUMBER 

 Jelly-fish. 



its organization shows it 

 ho^vn on the opposite page. A 

 expansion and contraction the 



These tentacles assist in locomotion, and it is by their means that 

 also believed to be sense organs. 



Most Sea Cucumbers burrow, worm-like, in the sand or mud. Some creep over the ocean floor ; 

 others lurk in rock crevices and in coral reefs ; whilst one species — already mentioned — swims like 

 a Jelly-fish, at the surface of the sea. 



About five hundred different kinds of Sea Cucumbers are known to science, and of these some 

 fifty are found in British waters. 



