NO. 7 PROTECTIVE ADAPTATIONS McATEE I3 



PLATYIIELMINTHES (fLATVVORMS, FLUKES) 



The majority of organisms of this phyhim are parasitic and there- 

 fore not available to predatory animals. Perhaps some of the fresh- 

 water planaria and the marine nemerteans have been found but not 

 identified in the stomachs of shore birds, but so far we have no 

 positive determination of a worm of this phylum as bird food. Forbes 

 reports a small catfish (Nohinis) feeding on fresh-water planaria. 

 Mcintosh says that marine planarians of both plainly and brightly 

 colored forms are eaten by sea-anemones and fishes. Fresh- water 

 planarians also are eaten by fishes. Stiles intimates that carp destroy 

 large numbers of the liver fluke (Fasciola licpatica) in the cercaria 

 stage. 



NEMATHELMINTHES (THREADWORMS, ROUNDWORMS) 



Again a vast number of worms of this phylum are parasites, abun- 

 dantly so, in fact, of birds themselves. In order to reckon as food 

 only those so taken, all nematodes other than Gordiidae have been kept 

 out of the computations. The records for Gordiidae number 24, the 

 percentage of these identifications among those of all animals is 

 .0101, and the percentage of known species' of Nemathelminthes 

 among all animals according to the estimates used in the present 

 paper, .2676. The nematodes have a tough cuticle but no special 

 defenses ; nevertheless they certainly are not eaten out of proportion 

 to their numbers, but considering availability to birds, they may 

 possibly be eaten somewhat in ratio to the frequency with which they 

 are encountered. They are eaten also by flatworms and by various 

 fishes. 



TROCHELMINTHES (rOTIFERs) 



None of these have yet been identified as food of nearclic birds, 

 though possiI)ly rotifers taken in with foliage of aquatic plants may 

 have been overlooked. Rotifers are eaten by the young of a number 

 of fishes. 



MOLLUSCOIDA ( CORALEINES, LAMPSHELLS) 



Protective adaptat'wns. — Except for the shells of the brachiopods, 

 and cuticular walls of some bryozoa, no special protective features 

 have been developed by the MoUuscoida. 



Bird enemies. — Only three brachiopods have as yet been identified 

 from the stomachs of nearctic bird.s — not a matter for surprise in 



^An enormous number of Nematodes await deseriptiou. 



