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with an araphipod, Ampelisca, and both the worm and the 

 snail communities were characterized by the presence of 

 mollusk genera such as Tellina „ Cylichna , Philine ,, Dentaliura, 

 Nucula , Macoma, , and polychaete genera such as Prionospio , 

 Magelona, Glycera , TerebellideSj, Sternaspis , Chaetozone , 

 and Praxillel lag all of which occur in nonpolluted areas 

 of southern Californiao 



Most of the species in the benthos of Santa Monica 

 Bay are believed to be endemic? that iSp they have restricted, 

 not cosmopolitan,, distributionso There are perhaps many 

 which are nearly related to some from similar habitats 

 in other temperate areas j and among the annelids these are 

 Gapitella eapitata^ Maldane sarsi, Chaetop terus vario - 

 pedatuS p Terebellides stroemi, Sternaspis scutata., 

 Scalibregma inf latumg and others » It is noteworthy 

 that although these are not easily distinguished 

 morphologically from their relatives in North Atlantic 

 areas, they may, by detailed study, show physiological 

 or other differences which may have more than varietal 

 signif icanceo For example, Chaetopterus variopedatus 

 is best known for constructing a U-shaped tube, largely 

 or fully embedded in the substratum except for its distal 

 ends, and it usually harbors commensals of several kinds 

 (a small fish and polynoid)o In southern California, 

 however, it forms dense clusters or irregularly tangled 

 tubes clumped together on the surface, and not embedded. 

 It has never been found to harbor a commensal. In most 



