118 BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



Bathymetrical range. From the shore line down to 73 meters. 



Occurrence. Dr. H. L. Clark says that this is a very common species at Broome, 

 and like all the Zygometras of that region it delights in the clean shallow water and 

 hard sandy bottom of Roebuck Bay. At extreme low water in the greatest spring 

 tides, as in September 1929, a large part of the water ebbs out of Roebuck Bay and 

 vast areas of a clean firm gray sand are exposed. On this bottom are countless 

 patches or isolated plants of coralline and other algae, besides partly buried rock 

 fragments or shells scattered abundantly about, well separated from one another, 

 and each forming the nucleus of a little animal community seeking shelter from the 

 pitiless exposure to which the unusual ebb of the tide subjects them. On almost 

 every alga or other projection a comatulid will be found, usually but one, and the vast 

 majority of these are Zygometras, chiefly comata. It is a hardy species, enduring this 

 exposure to the sun, transferring to a bucket, and transportation to the laboratory 

 without damaging itself in any way. Left by the retreating tide, the comatulids fall 

 relaxed on their sides, the arms closed on the disk and pointing to the water that has 

 abandoned them. But when the tide returns, enduring for a time the washing 

 back and forth of the now coming, now going, wavelets, they soon find the water deep 

 enough to enable them to sit erect, expand their arms, and renew their normal life. 

 Dr. Clark says that seeing this flowerlike expanding of the wilted comatulids is one 

 of the most interesting pleasures of watching the incoming tide. 



History. In sending some myzostomes taken from a comatulid collected by Dr. 

 John Anderson at King Island in the Mergui Archipelago to Prof. Ludwig von Graff 

 for identification, Dr. P. H. Carpenter gave the name of the host as Antedon comata. 

 This name was published as a nomen nudum by Professor von Graff in 1887, together 

 with the locality. It was never mentioned again either by von Graff or by Car- 

 penter. Von Graff gave as the locality "Padau Bay in the Mergui Archipelago." 

 Carpenter said (later) that all the comatulids collected by Anderson at Mergui were 

 obtained at one locality, King Island. Therefore Padau Bay, which I can not locate 

 in any of the available books of reference, must be on the shore of King Island, and is 

 possibly the same as King Island Bay, the main anchorage at King Island. 



In discussing Antedon elegans in the Challenger report in 1888 Carpenter said 

 that Professor Semper's Philippine collection contained representatives of the type 

 and that he had recently found a most valuable series of varying forms of this species 

 among the comatulids dredged by Dr. Anderson in the Mergui Archipelago. These 

 Philippine and Mergui specimens represent not Zygometra elegans but Z, comata. 

 In 1888 Prof. F. Jeffrey Bell mentioned that Dr. Anderson had collected Antedon 

 elegans [= Zygometra comata] in the Mergui Archipelago. 



Under the name Antedon elegans Carpenter in 1889 recorded and gave notes 

 upon the five specimens collected by Dr. Anderson at King Island in the Mergui 

 Archipelago. He compared these with the specimens obtained by the Challenger 

 and by the Alert (representing true elegans) and noted the differences. He mentioned 

 a feature exhibited by the Mergui specimens in common with, and more distinct in, 

 others from the Philippines in Semper's collection. 



Carpenter said that there were in the collection of comatulids from the Mergui 

 Archipelago three species of "Antedon" infested with myzostomes, and that these 

 myzostomes had been placed in the hands of Professor von Graff for identification 



