PART II. 



HABITS AND REACTIONS. 

 MATERIAL. 



Crinoids are so abundant and easily obtained at Maer that there was 

 no lack of material for study, but experience unfortunately showed 

 that the species with which the most interesting results might have 

 been obtained were so uncommon as to be unavailable for experimental 

 work, while the most abundant species were very sluggish and often 

 unsatisfactory to deal with. Moreover, individual differences were 

 quite marked, more so than I had expected, and led of course to incon- 

 sistent results. The commonest comatulids, the young individuals of 

 Comatula purpurea, proved less satisfactory for experimental work 

 than adults of the same and of larger species, as they are rather inert, 

 responding slowly to stimuli; but many observations were made on 

 their behavior under normal conditions on the reef. Most of my 

 observations and nearly all the experiments at the laboratory were 

 made on adult Comatula purpurea, Comatella maculata and stelligera, 

 and Comanthus annulatum. Of these, the last was the most easily avail- 

 able, but it was not so active as the others. Everything considered, 

 adults of Comatula purpurea were found the most satisfactory for 

 purposes of study, as their responses to stimuli seemed to be more 

 prompt and more marked than in any other individuals, and the results 

 were more consistent. Unfortunately these available comatulids are 

 all members of the family Comasteridse and had many traits in com- 

 mon. The comparatively few individuals of the families Stephano- 

 metridae, Mariametridse, Colobometridse, and AntedonidaB, which I had 

 the chance to watch, showed that they differ from the Comasteridse 

 as much in habits as in structure. They are good swimmers and 

 would be exceedingly interesting to study critically in the laboratory. 



All but two of the crinoids seen by me were found either on the 

 lower surface of rock-fragments or among the branches of stony coral 

 of various species. They occurred on different parts of the reef-flat 

 about Maer, but except the ubiquitous Comatula purpurea, they were 

 virtually confined to the southern end and eastern side of the island. 

 They were usually in water not less than 2 or 3 feet deep at low tide, 

 but occasionally when the tide was very low they were in water only 

 a few inches deep. Twice specimens were found in the cavities of 

 large sponges, and it is possible that outside the reef this may be a 

 common habitat. Owing to the lack of facilities for dredging, no 

 observations were possible on crinoids living in the deeper water 

 beyond the reef. 



It was a pleasant surprise to find that with few exceptions the 

 crinoids at Maer were not nearly as delicate and frail as their exquisite 



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