ACTINIARIA 



of contraction, and the longitudinal furrows of the tentacles of clavus have no doubt arisen by an accidental, 

 irregular contraction (compare above!). The longitudinal pennons of H. kerguclensis are not so richly rami- 

 ficated as in Halcampa purpurea, and the folds are thicker than in the latter species which I have above 

 proved to be identical with H. clavus, but this diversity is, in my opinion, due to the different age of the 

 specimens (the specimens of kerguelensis were considerably smaller than those of purpurea) . I therefore think 

 that Hertwig's H. clavus and kerguclensis and Studer's H. purpurea, all dredged at Kerguelen, are the 

 same species. 



If we now turn to the Northern and Arctic Halcampoides-species, Appellof (1896) has shown that 

 Fenja mirabilis and Aegir frigidus are identical with H. abyssorum, a view which is correct, as far as I can 

 see from Appellof's description. In addition to Danielssen's species we have to recollect H. septentrio- 

 nalis, a name proposed by Pax for Halcampa clavus, described by Tizard and Murray, from the channel 

 of the Faroe Islands and, according to Haddon (1889, p. 336), identified by R. Hertwig as his H. clavus. 

 As this form has been dredged in the cold area, it is very probable that it is identical with abyssorum (I have 

 never seen this form myself) ; there is no reason to give a new name to this form, and Me. Murrich (1913, 

 p. 969) is of the same opinion. Finally we have to mention Halcampoides elongatus, a species which I have 

 characterized in a few words (in Stephens 1912, p. 8) as having weaker and more elongated parietal muscles 

 than H. abyssorum. As I have, however, afterwards found (compare above, textfigs. no in) that the 

 parietal muscles in young, not adult specimens of abyssorum are provided with sparser folds and are more 

 elongated in the part belonging to the reproductive region than in older specimens, I think that the sup- 

 posed differences in the structure of the parietal muscles of elongatus and of abyssorum are connected with 

 a disparity of age the specimens of elongatus were young, not adult specimens, and I am probably not mis- 

 taken, if I place H. abyssorum, septentrionalis and elongatus together in a single species, H. abyssorum. 



The question now remains, whether Halcampoides purpurea and H. abyssorum are identical or not. 

 Almost all authors occupying themselves with this question, as Haddon, Me. Murrich and Pax, have re- 

 garded the Antarctic and Arctic species of Halcampoides as distinct species in fact no author has examined 

 more than a few of the above-named species, but entirely founded his statements on descriptions from literature. 

 Appellof (1896) is the only author who has proposed Hertwig's H. clavus and Danielssen's Hakampoides 

 abyssorum to be the same species; still R. Hertwig has identified H. clavus with the species signified as 

 H. septentrionalis. With an interrogation-mark Appellof has also put up H. clavus Quoy and Gaim. as syno- 

 nymous with the former as well as with Halcampa purpurea. On the other hand, he keeps Hakampoides 

 kerguelensis as a distinct species. After the account given above I have had an opportunity to examine 

 all species excepting H. septentrionalis I do not doubt that they are all identical or, on all accounts, so 

 nearly related that no specific character can be pointed out for them. The species therefore ought to be called 

 Halcampoides purpurea (Stud.) Carlgr. 



Thus we find here a species occurring now in deeper, now in more shallow water, common to the 

 Arctic as well as the Antarctic regions, but, according to earlier accounts, absent in the intermediate waters. 

 The latter account is, however, probably not correct ; I am inclined to think that the species is to be regarded 

 as a cosmopolitan, though it has its largest distribution in the cold area. The occurrence of the species in the 



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