1912-13.] Hyclroids of British Antarctic Expedition, 1998. 17 
East Greenland, Halecium groenlandicum, Kramp,* in which the author 
has found aggregates of reproductive bodies remarkably like those of 
Ophiodes arboreus, a species to which Kramp makes no reference. The 
trophosome of the Arctic species differs, however, from that of the 
Antarctic, and in the former nematophores have not been observed. 
Dimensions . — 
Internode, length .... 0*55-1 *08 mm. 
diameter . . . 0'22-0‘35 mm. 
Hydrotheca, diameter . . . 0*26-0‘30 mm. 
depth . . . 0’06-0085 mm. 
Gonangium, length . . . T02-T09 mm. 
Greatest diameter .... 0*49-0'52 mm. 
Localities. — M‘Murdo Sound, 25-50 fathoms, 6th July 1908 (gonangial 
clusters). Cape Royds, 20-30 fathoms, July 1908 ; 30-60 fathoms, 15th 
August 1908 (stem fragments); 30-80 fathoms, August 1908 (stem frag- 
ments) ; 50-80 fathoms, 20th August 1908, and 60-80 fathoms, 20th August 
1908 (gonangial clusters). 
Distribution. — The only secure records of this species are : off Kerguelen 
Island, 105 fathoms (Allman), and the Antarctic Ross Island records of 
Hickson and Gravely, together with those given above. 
Note on Synonymy. — As regards the two specific names which Allman 
used in his original description, preference has generally been given to 
arboreum, but Vanhoffen rejects this in favour of robustum, alleging that 
the former is only a mistaken subscription to the figure. This view cannot 
be maintained. Allman originally named the species Halecium robustum, 
but this name had been used for a different species of Halecium by Verrill 
in 1873, and again by Pieper in 1884, and, probably having discovered this, 
Allman was compelled to select a new specific name. This he publishes in 
the text which accompanies the plate representing his species, as Halecium 
arboreum, and adds that he has found it “ necessary to change the name 
since the plate was printed off”; the name on the plate is “ robustum .” 
This last name, therefore, cannot stand. 
As to the transference of the species to the genus Ophiodes, Hickson 
and Gravely have by comparison identified their specimens with the type 
specimens. On both, nematophores occurred on the internodes, a fact which 
Billard has confirmed for Allman’s type, and which my present specimens 
also confirm. This is the distinctive and definite character of the group of 
species referred to Ophiodes, and it appears to me that more evidence is 
required before the character can be regarded as of so little importance 
* Kramp, 1911, p. 367, pi. xxii. 
VOL. XXXIII. 
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