ECHINODERMS 63 



confined mainly to the abyssal ocean. In prehistoric times 

 vast areas of the sea floor must have presented the appear- 

 ance of being covered with 12-ft. or 20-ft. palm trees, 

 whose branches clutched restlessly at the water above and 

 having caught small organisms, passed them to a hungry 

 mouth in the centre of the leaves. 



The Crinoides or Sea Lilies are not unlike the Starfish, 

 having five pairs of feathery arms with a mouth pointing 



Rosy Feather Star (Atitedori) 



upwards, the whole poised upon a long jointed stem 

 firmly anchored by rootlike outgrowths to the sea floor. 

 A few are without stalks and have free locomotion, but 

 the majority are anchored for life. This interesting group 

 is represented in the tidal zone of our south-western 

 shores by a single species only — the Rosy Feather Star 

 (Antedon bifida). It has ten jointed feathery arms which 

 move always in pairs and can row the creature here and 

 there, whilst when desiring to rest a tuft of rootlike 



