12 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 85 



sand launce, lump sucker, cunner, scup, filefish. and flatfishes ; cteno- 

 phores are eaten by the spiny dogfish, flatfishes, whiting, and cod; 

 sea-anemones are eaten by cod,^ haddock, tilefish, flatfishes, the sun- 

 fish Mola, spiny dogfish, whiting, and by the so-called jellyfishes and 

 by whales. Holothurians and some fishes (Scams) feed on corals. 



Mcintosh notes that the brightly colored jellyfishes " have precisely 

 the same habits as the uncoloured and transparent," which raises 

 doubt as to the validity of the selectionist interpretation of the facts. 

 The brightly hued and the translucent forms are equally palatable 

 to whales and other animals using jellyfishes as food. He adds with 

 regard to sea-anemones that " the view that the gaudy colors .... 

 act as a warning is not borne out by the eagerness with which the 

 cod swallows the brightest, such as Stomphia, while the smaller flat- 

 fishes fill their stomachs with Edzvardsiae." (Ann. Mag. Nat. Hist. 

 7th ser., vol. 7, pp. 224-225, 1901.) 



Discussion. — Coelenterates are another group of animals but 

 slightly available to birds and seem to be taken in full proportion to 

 the degree of availability. The nematocysts seem a futile defense 

 against animals of the groups here mentioned as coelenterate enemies, 

 and must be also in the case of the myriads of Crustacea (possible 

 enemies) all of which have a chitinous exterior and which more- 

 over manipulate their food in the chelae before chewing it, a process 

 that would result in the harmless discharge of the stinging cells. 

 It is alleged that hermit crabs have a commensal relation with certain 

 hydroids which grow upon the shells they inhabit and that they are 

 protected from their enemies by the presence of the inedible stinging 

 hydroids.' This is not the case where the bird enemies are concerned, 

 as the sea ducks which are the principal bird enemies of hydroids, 

 often swallow the hermit crab, shell, hydroids and all. Many of the 

 examples identified from bird stomachs came from precisely this 

 source. With respect to the practical aspect of the case, it would 

 appear that in its shell retreat and its own strong claws the hermit 

 crab has much more efficient defenses than the nettlelike hydroids. 

 It seems more likely that the latter merely grow on mollusk shells as 

 a convenient substratum. From the habit some hermit crabs have of 

 frequently changing their abode, the advantage held by a "com- 

 mensal " hydroid may be lost at any moment. 



^ Mcintosh notes that sea-anemones are a valued bait for cod. 

 " Parker and Haswell, Zoology, vol. i, p. 144, 1910. 



