NOTES ON SOME PROBLEMS OF ADAPTATION. 113 



In view of the absolute lack of any concealing behavior prac- 

 ticed by these creatures, I tried at various times to feed pieces 

 of the skin to fishes ("squirrels," yellow grunts, gray snappers, 

 and other common shore forms, including the hamlet). Such 

 trials were invariable unsuccessful, the flesh being refused. 

 And, as Minchin ('92) long ago found, the intestine and respira- 

 tory trees are likewise rejected as food. 



It is of interest to note that, in spite of such evidence of "un- 

 palatability, " which may perhaps be supplemented from 

 Bartsch's ('17) account of the use of "holothurians" by the 

 natives of Guam in driving Octopus from its "nests," holo- 

 thurians are nevertheless occasionally seen in the role of hosts 

 for erratic ectoparasites, which in some instances eat from their 

 skin. Chatton ('09) found an ascidian attached to and growing 

 on the integument of Holothuria, and I have seen a young 

 actinian (Condylactis) firmly affixed to the integument of a 

 Stichopus. Quite apart from such molluscan forms as Stylifer, 

 one species of which I have found in considerable numbers on 

 S. mcebii, I have records of an annelid (an unidentified species of 

 Odontosyllis} and of a polyclad worm, Leptoplana, feeding on the 

 skin of Holothuria Surinam ensis; the gut of the worm was in each 

 of these cases filled with the bright green integumentary pigment 

 of the host. So that it is difficult to postulate for these animals 

 the possession of any generalized repellent secretion. Plate 

 ('16), also, has described a polynoid and a crab, both homo- 

 chromic in coloration, living upon Holothuria atra. 



On the other hand, Holothuria surinamensis has on several 

 occasions been found bearing clear evidence of injury. One 

 specimen was picked up, lying in the open on a sandy bottom 

 with a shallow gouge cut along the whole length of the body; 

 in all probability it had been nipped by a crab, perhaps Callinectes. 

 Later, three others were obtained, all injured in a similar way. 

 In the absence of some repellent "flavor," it is difficult to under- 

 stand why the holothurians, once bitten into in this way, should 

 have been dropped. This particular species, as I have said, is 

 devoid of Cuvierian organs, and in the mangrove creeks where it 

 notably abounds it comes to the surface only at night, being 



