The most interesting forms brought to light by the Norwegians are the two genera Fenja and Aegir, animals possessing the general form of sea anemones but distinguished from all Cœlenterates by the presence of a continuous and straight gut reaching from the mouth to the aboral pores which completely shuts off the cœlenteron or general body cavity from the stomodæum.
In more recent times the work has been by no means neglected. With the advantage of employing many modern improvements in the dredges and trawls in use, the American steamer, the ‘Albatross,’ has been engaged in a careful investigation of the deep-sea fauna of the eastern slopes of the Pacific Ocean, while at the same time Her Majesty’s surveying vessel, the ‘Investigator,’ has been obtaining some interesting and valuable results from a survey of the deep waters of the Indian Ocean. But our knowledge of this vast and wonderful region is still in its infancy. We have gathered, as it were, only a few grains from a great unknown desert. It is true that we may not for many years, if ever, obtain any results that will cause the same deep interest and excitement to the scientific public as those obtained by the first great national expeditions, but there are still many important scientific problems that may be and will be solved by steady perseverance in this field of work, and if we can only obtain the same generous support from public institutions and from those in charge of national funds that we have received in the past two decades, many more important facts will doubtless be brought to light.
CHAPTER II
THE PHYSICAL CONDITIONS OF THE ABYSS
It is not surprising that the naturalists of the early part of the present century could not believe in the existence of a fauna at the bottom of the deep seas.
The extraordinary conditions of such a region—the enormous pressure, the absolute darkness, the probable absence of any vegetable life from want of direct sunlight—might very well have been considered sufficient to form an impassable barrier to the animals migrating from the shallow waters and to prevent the development of a fauna peculiarly its own.
The fragmentary accounts of animals brought up by sounding lines from great depths might, it is true, have thrown doubts on the current views; but they were not of sufficient importance in themselves, nor were the observations made with such regard to the possibility of error, as to withstand the critical remarks that were made to explain them away.
The absence of any evidence obtained by accurate systematic research, together with the consideration of the physical character of the ocean bed, were quite sufficient to lead scientific men of that period to doubt the existence of any animal life in water deeper than a few hundred fathoms.
We now know, however, that there is a very considerable fauna at enormous depths in all the great oceans, and we have acquired, moreover, considerable information concerning some of those peculiar physical conditions of the abyss that fifty years ago were merely matters of speculation among scientific men.
The relation between animals and their environment is now a question of such great interest and importance that it is necessary in any description of the fauna of a particular region to consider its physical conditions and the influence that it may be supposed to have had in producing the characteristics of the fauna.
The peculiar physical conditions of the deep seas may be briefly stated to be these: It is absolutely dark so far as actual sunlight is concerned, the temperature is only a few degrees above freezing point, the pressure is enormous, there is little or no movement of the water, the bottom is composed of a uniform fine soft mud, and there is no plant life.