14 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 85 



view of the small number and marine habitat of the species of these 

 animals. The other MoUuscoida that have been found in bird stomachs 

 include Cyclostomata (having calcareous zooecia), Cheilostomata 

 (with calcareous or chitinous zooecia), and Phylactolaemata. Large 

 numbers of the statoblasts of the latter group, the fresh-water bryozoa, 

 have been disclosed in the stomachs of wild ducks. 



Number of identifications of MoUuscoida, 134; percentage of 

 identifications among those of all animals, .0564 ; percentage of species 

 in this phylum among the whole number of animal species known, 



•3032. 



Discussion. — Considering their low availability to birds, animals of 

 this phylum probably are taken in due proportion. Fresh-water bryo- 

 zoans have been recorded from stomachs of many species of fishes, 

 and the marine forms from a smaller number. Marine bryozoans 

 are preyed upon by worms, amphipods, decapods, and starfishes. 



ECHINODERMATA (SEA-CUCUMBERS, SEA-URCHINS, STARFISHES) 



Protective adaptations. — All of the echinoderms have a calcareous 

 exoskeleton and in many the surface is beset with tubercles or spines. 

 The starfishes and sea-urchins are armed also with pedicellariae or 

 grasping organs, which in some cases in the latter group are said to 

 be poisonous. Some sea-cucumbers have the " Cuvierian organs " 

 which throw out long viscid filaments. Starfishes, especially the 

 brittlestars and many crinoids, have the supposedly protective faculty 

 of snapping oiT their arms or portions thereof. The colors of echino- 

 derms are often conspicuous and in certain cases have been termed 

 warning. 



Bird enemies. — Starfishes have been identified 28 times in the 

 stomaclis of nearctic birds here reported upon ; sea-urchins (Stroiif/yl- 

 ocentrus, Ecliinarachnius) 92 times; and sea-cucumbers, 3 times. 

 The birds (19 species) eating them were chiefly ducks collected in 

 northern seas. 



Number of identifications, 125 ; percentage of identifications among 

 those of all animals, .0526; percentage of species in this phylum among 

 the whole number of animal species known, ./^^f^. 



Other enemies. — Starfishes and sea-urchins prey upon one another, 

 and are very commonly eaten by cod, haddock and other species of 

 Gadus, by argentines, dragonets, rocklings, wolfiishes, rays, sharks, 

 tautog, scup, smelt, flatfishes, and others. Sea-cucumbers are less 

 commonly taken by the same predators. Blue foxes on the Pribilof 

 Islands feed on sea-urchins in winter. Sea-urchins and starfishes are 

 consumed also bv crabs, sea-anemones, and marine worms. 



