Euplectella (Venus's flower baskets)

Perhaps the most beautiful of glass sponges belong to the genus Euplectella, popularly known as the Venus's flower baskets'.  Their dried specimens or intricately-latticed skeletons are often seen in museums.  They grow in deep water.  

Euplectella aspergillum is especially the Philipine islands, while abundant E suberea occurs off the West Indies.  These are long, curved, thin-walled and cylindrical tubes, 15 to 30 cm long and 2.5 to 5 cm in diameter.  Curved and rigid structure is an adaptation to slow constant water current found at depths from 500 to 5000 meters.  Body is held up by skeleton made of four and six-rayed siliceous spicules fused at their tips and much united by cross-bars forming the intricate lacework.  Beautiful to look at, the near Venus's flower baskets are unpleasant to handle as the spicules projecting through the surrounding protoplasmic material prick the fingers.  Gleaming white skeletons look fragile and delicate but they are surprisingly strong, and nearly perfect ones are often washed up on the beaches.  Terminal opening at the upper end is closed by an oscular sieve plate formed of fused spicules.  Openings or parietal gaps, seen in the meshwork of spicules, although connected with spongocoel, do not form part of canal system which is of simple sycon type.  Flagellated chambers lie radially in the sponge wall.  

Sponge is fastened in mud of sea bottom by a tuft of root-like, long and siliceous threads arising from lower end of body.  Root spicules are adapted to anchor sponge to its unstable substratum of slimy oceanic ooze.  

Species of Euplectella exhibit a commensal association with certain species of shrimps.  Young male and female shrimps enter the spongocoel of sponge and after growth are unable to escape through the minute sieve plates of osculum.  They lead their entire life within the sponge, feeding on plankton brought in with the ingressing water current.  The sponge with its imprisoned shrimps makes a good wedding gift in Japan, symbolizing the idea 'till death us do part'.