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BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



The disk (which is 10 mm. in diameter) and the ambulacra arc naked. Sacculi 

 are abimdant in some places, but less so in others. 



The color in alcohol is white, with purplish or brownish patches. 



Carpenter said that tliis is a smaller and more delicate species than Antedon ant- 

 ardica, which it resembles in the shortness of its brachials; but the arms generally are 

 much smoother, and there are fewer cirrus segments, while P3 is much less like P2 than 

 is the case in that species. The 3 lowest segments of P3 are by no means so broad as 

 in A. antarctica, but more nearly square, while the following segments until quite near 

 the end are very distinctly longer than broad, which is not the case in A. antarctica. 

 Even the first 2 pinnules of A. australis have a tendency in this direction, as compared 

 with the much longer ones of Heliometra glacialis and Solanometra avtarctica. 



It can scarcely be doubted that Antedon australis was based upon structurally 

 immature individuals of Solanometra antarctica. 



The types of australis were 7 specimens from Challenger station 150 ofif Heard 

 Island and a mutilated specimen of much smaller size from which aU the arms had 

 been broken away at tlie syzygy between brachials 3 + 4. 



[Notes by A.M.C] A comparison of the figures given in the table shows some 

 differences between the specimens from Heard Island and those from Adehe Land. 

 The latter appear to have relatively higher centrodorsals, slightly narrower arms, 

 longer cirri with more and longer segments (fig. 18a,e) and proximal pinnules with fewer 

 segments, taldng the size into consideration, although at least one of the types of 

 antarctica (that in the M.C.Z.) has cirri with up to 35 segments. 



I suspect that these larger specimens from the Australasian Antarctic Expedition 

 (Aurora) collections are conspccific with the smaller ones from Adelie as well as Queen 

 Mary Lands, which Mr. Clark described as a new species, Florometra mawsoni. In 

 his key to the comatulids of the Southern Ocean given in the report of that expedition 

 (1937), Mr. Clark distinguished S. antarctica from F. mawsoni by the larger size, more 

 numerous (60:36) segments of Pi, more numerous (c.40:30) cirrus segments, "most of 

 which are not longer than broad," (they may be so in the types of aniarciica from Heard 

 Island but at least one Adelie Land specimen has 20 out of the 41 segments of a periph- 

 eral cirrus distinctly longer than broad and the longest just over twice as long as broad) 

 and by the broader brachials of which the proximal ones are smooth. All these char- 



Table 12. — Details of six specimens of S. antarctica /rom two Challenger stations off Heard Island, 

 and of two specimens also recorded under this name from Adelie Land 



