IV.—Supplementary Report on the Hydroids of the Scottish National Antarctic Expedition

Since the report on the Hydroids collected by the Scotia was completed, almost three years ago, I have had an opportunity, thanks to the kindness of Dr W. S. Bruce, of looking through the enormous mass of material brought together by him during his Antarctic voyages. The search, begun in the hope of finding a few minute species—which, since many are epizoic on other forms of marine life, might readily be overlooked on cursory examination—has resulted in the addition of no less than 25 forms to the 36 already recorded. Deducting from this total of 61 forms two varieties, it appears that the Scotia collection contains in all 59 distinct species. Few, indeed, of these have been obtained in truly Antarctic latitudes—subantarctic or temperate seas having furnished the greater number—but this result is in accordance with the findings of the majority of the recent Antarctic expeditions. Dr Billard, in summarising the results of the Belgian, Swedish, and French expeditions, states that the known Hydroid fauna of Antarctic regions comprises only 32 species. But from his list he has, I think unjustly, excluded South Georgian records. His list, moreover, published before the valuable paper by Professor Hickson and Mr Gravely on the Discovery Hydroids was issued, necessarily makes no reference to the large number of forms recorded by them from Victoria Land.