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PHYLA OF LESSER SIGNIFICANCE 







Photo by Winchester 



Fig. 18.2. Rotifers. 



back quickly at the slightest sign of danger. Superficial examination 

 might lead to their inclusion with the Coelenterates because of their ex- 

 ternal similarity to the polyp body shape, but further study reveals a 

 brain and an anus which definitely rank them as being more advanced. 



Phylum — Phoronidea 



This is a small group of about a dozen species of sessile, marine, 

 worm-like animals that secrete a hard tube in which they dwell. They 

 extend themselves to feed and withdraw into the tube in times of danger 

 like the bryozoans. 



Phylum — Brachiopoda 



The Brachiopoda bear an external resemblance to bivalved mollusks. 

 They have two valves to their shell held together with a hinge, but there 



