The Eiitoprocts 



(Phylum Entoprocta) 



These are tiny (less than '4 of an inch high) 

 aquatic animals that live as solitary individuals or 

 little colonies, superficially resembling hydroids be- 

 cause the round or bell-shaped, flower-like body sup- 

 ported on a stalk is crowned by an oval circlet of 

 tentacles. 



Under the microscope, an entoproct's tentacles are 

 seen to be ciliated on their inner surfaces and to cre- 

 ate ciliary feeding currents that gather microscopic 

 organisms and particles. The intestine is U-shaped; 

 and this, together with the tentacular crown and the 

 habit of growing attached to various objects or on 

 other animals, reminds us of the familiar moss ani- 



mals (bryozoans). For many years, in fact, the en- 

 toprocts were included within the phylum Bryozoa. 

 But the body of an entoproct differs from that of a 

 moss animal in so many ways that a separate phylum 

 became necessary for them. It is named for the posi- 

 tion of the anus — within the circlet of tentacles. In 

 moss animals the anus opens outside the tentacular 

 crown. In hydroids, of course, there is no anus. 



Entoprocts are almost entirely a marine group. So 

 far the only fresh-water genus (Urnatella) has been 

 found in India and the eastern part of the United 

 States. The remainder of the sixty-odd known species 

 of entoprocts have been collected widely on marine 

 shores or in shallow waters around the world. Find- 

 ing these inconspicuous animals is an exciting chal- 

 lenge to anyone who likes to see at first hand a small 

 group known to most people only from books. 



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