608 BULLETIN 82, UNITED STATES NATIONAL MUSEUM. 



of its pedicel was originally attached, the former can quit its hold when its attach- 

 ment is no longer suitable to its requirements, and can move from place to place in 

 search of another. How intimate, moreover, is the fundamental relation between 

 the dorsal cirri of the adult Antedon and the column of its pentacrinoid larva 

 further appears from the fact that the cirri only make their appearance in the 

 later part of the pentacrinoid stage in preparation for that detachment of the 

 crown from the column which thenceforth changes the condition of the animal from 

 the fixed to the free. 



Doctor Carpenter summarizes the results of his observations as follows: The 

 life of the adult Antedon is habitually passed (I feel justified in asserting) so 

 nearly in the same degree of fixedness as that of its pentacrinoid larva that it may 

 almost equally be regarded as representing the life of the typical Crinoidea. If 

 the creature ever quits its attachment, save on account of the unsuitableness of its 

 position, it is probably during the period of sexual activity, at which it seems more 

 frequently errant than at any other stage of its life except the earliest. 



Mr. Herbert C. Chadwick, who has enjoyed altogether exceptional opportuni- 

 ties for observing Antedon bifida at the Isle of Man, agrees with Carpenter. He 

 says that Antedon is not usually an active animal; by means of its cirri it clings 

 tenaciously to stones, algae, hydroids, etc., the arms being widely spread hori- 

 zontally, with the tips more or less flexed toward the disk. When disturbed it 

 swims actively and with strikingly graceful movements, the two arms of each pair 

 being invariably flexed and extended alternately. 



He also says that it is often found clinging by means of its cirri to the wicker 

 creels used by fishermen for the capture of lobsters and crabs. The fishermen state 

 that specimens are always more numerous on the creels after stormy weather. 



In a letter to Mr. Frank Springer, dated September 6, 1900, Mr. Alexander 

 Agassiz wrote: 



I take it you know that Comatulse are excellent swimmers, striking out with their arms 

 and moving about from point to point in Oorgonia groves. It is not uncommon to see a number 

 swimming in a school among the Oorgonias. 



In a letter to Dr. H. L. Clark, Dr. L. E. Griffin, of the Bureau of Science, 

 Manila, said: 



I saw in Science that you discovered crinoids swimming at Mae'r. One I sent you from 

 Oulion was a very active swimmer and lived among the eelgrass. We have often seen them 

 swimming in the Philippine Islands. 



In recently captured individuals of Antedon adriatica Reichensperger in rare 

 cases observed a sort of slow progress by means of slow movements of the cirri, 

 assisted by similarly slow movements of the arms. The tracks made by the cirri 

 in fine sand were afterwards clearly visible. 



In 1866 Jeffreys mentioned that specimens of Leptometra celtica had been 

 found clinging to the rope of a dredge some distance above the end, and in 1895 

 Bather suggested that these individuals may have been swimming about and there- 

 fore may have attached themselves to the rope as it passed by. 



