Chapter I: Preface

The time may come when there will be no portion of the earth’s surface that has not been surveyed and explored by man.

The work of enterprising travellers has now been carried on within a measurable distance of the North Pole; the highest mountain ranges are gradually succumbing to the geological surveyor; the heart of Africa is giving up to us its secrets and its treasures, and plans of all the desert places of the earth are being made and tabulated.

The bottom of the deep sea was until quite recently one of these terræ incognitæ. It was regarded by most persons, when it entered into their minds to consider it at all, as one of those regions about which we do not know anything, never shall know anything, and do not want to know anything.

But the men of science fifty years ago were not disposed to take this view of the matter. Pushing their inquiries as to the character of the sea-fauna into deeper and deeper water, they at length demanded information as to the existence of forms of animal life in the greatest depths. Unable themselves to bear the heavy expenses involved in such an investigation, they sought for and obtained the assistance of the Government, in the form of national ships, for the work, and then our knowledge of the depths of the great ocean may be said to have commenced.

We know a good deal now, and in the course of time we may know a great deal more, about this interesting region; but it is not one which, in our generation at any rate, any human being will ever visit.

We may be able to plant the Union Jack on the summit of Mount Everest, we may drag our sledges to the South Pole, and we may, some day, be able to travel with ease and safety in the Great Sahara; but we cannot conceive that it will ever be possible for us to invent a diving-bell that will take a party of explorers to a depth of three and a half miles of water. We may complete our survey of the ocean beds, we may analyse the bottom muds and name and classify the animals that compose their fauna, but there are many things that must remain merely matters of conjecture. We shall never know, for example, with any degree of certainty, how _Bathypterois_ uses its long feeler-like pectoral fins, nor the meaning of the fierce armature of _Lithodes ferox_; why the deep-sea Crustacea are so uniformly coloured red, or the intensity of the phosphorescent light emitted by the Alcyonaria and Echinoderms. These and many others are and must remain among the mysteries of the abyss.

Our present-day knowledge of the physical conditions of the bottom of the deep sea and the animals that dwell there is by no means inconsiderable.

It may be found in the reports of the scientific expeditions fitted out by the English, French, German, Italian, Norwegian, and American Governments, in numerous volumes devoted to this kind of work, and in memoirs and notes scattered through the English and foreign scientific journals.

It is the object of this little book to bring together in a small compass some of the more important facts and considerations that may be found in this great mass of literature, and to present them in such a form that they may be of interest to those who do not possess a specialist’s knowledge of genera and species.

When it was found that animals can and do live even at the greatest depths of the ocean, the interest of naturalists was concentrated on the solution of the following problems. Firstly, do the animals constituting the fauna of the abyss exhibit any striking and constant modification in correlation with the physical conditions of their strange habitat? And, secondly, from what source was the fauna of the abyss derived? Was it derived from the shallow shore waters, or from the surface of the sea? Is it of very ancient origin, or the result of, comparatively speaking, recent immigrations?

These questions cannot be answered in a few lines. Any views that may be put forward regarding them require the support of a vast array of facts and figures; but as the limits of this little book would not permit of my giving these, I have endeavoured to select a few only of those which bear most directly upon the points at issue.

To overburden my work with the names of genera or the lists of species would not, it seemed to me, either clear the issues or interest the general reader. These may be found in the ‘Challenger’ monographs, and other books dealing with the subject.

Those who wish to pursue the subject further will find in the ‘Voyages of the “Blake,”’ by Alexander Agassiz, an excellent and elaborate discussion of deep-sea problems, and numerous illustrations of some of the most interesting forms of abysmal life.

In Volume XXIII. of the ‘Bulletin of Comparative Zoology’ the same author gives a most interesting account of the deep-sea work that has recently been done by the ‘Albatross’ expedition.

Filhol’s ‘La Vie au Fond des Mers’ is also a book that contains a great deal of new and interesting matter, together with some excellent coloured plates of deep-sea animals.

SYDNEY J. HICKSON.

DOWNING COLLEGE, CAMBRIDGE:
_September, 1893_.

CONTENTS

CHAPTER PAGE
I. A SHORT HISTORY OF THE INVESTIGATIONS 1

II. THE PHYSICAL CONDITIONS OF THE ABYSS 17

III. THE RELATIONS OF THE ABYSMAL ZONE AND THE ORIGIN OF ITS
FAUNA 45

IV. THE CHARACTERS OF THE DEEP-SEA FAUNA 59

V. THE PROTOZOA, CŒLENTERA, AND ECHINODERMA OF THE DEEP SEA 86

VI. THE VERMES AND MOLLUSCA OF THE DEEP SEA 109

VII. THE ARTHROPODA OF THE DEEP SEA 123

VIII. THE FISH OF THE DEEP SEA 148

INDEX 167

LIST OF ILLUSTRATIONS

STOMIAS BOA. AFTER FILHOL, ‘LA VIE AU FOND DES
MERS’ _Frontispiece_

FIG. PAGE
1 DIAGRAM ILLUSTRATING THE PASSAGE OF AN OCEAN
CURRENT ACROSS A BARRIER 32

2 _Sicyonis crassa._ AFTER HERTWIG, ‘“CHALLENGER”
REPORTS’ 36

3 GLOBIGERINA OOZE. AFTER AGASSIZ, ‘VOYAGES OF THE
“BLAKE”’ 38

4 SECTION THROUGH THE EYE OF _Serolis schythei_.
AFTER BEDDARD, ‘“CHALLENGER” REPORTS’ 74

5 SECTION THROUGH THE EYE OF _Serolis bromleyana_.
AFTER BEDDARD, ‘“CHALLENGER” REPORTS’ 74

6 _Opostomias micripnus._ AFTER GÜNTHER,
‘“CHALLENGER” REPORTS’ 78

7 HEAD OF _Pachystomias microdon_. AFTER VON
LENDENFELD, ‘“CHALLENGER” REPORTS’ 79

8 SECTION THROUGH THE ANTERIOR SUB-ORBITAL
PHOSPHORESCENT ORGAN OF _Pachystomias microdon_.
AFTER VON LENDENFELD, ‘“CHALLENGER” REPORTS’ 80

9 _Challengeria Murrayi._ AFTER HAECKEL,
‘“CHALLENGER” REPORTS’ 90

10 _Umbellula Güntheri._ AFTER AGASSIZ, ‘VOYAGES OF
THE “BLAKE”’ 97

11 _Rhizocrinus lofotensis._ AFTER CARPENTER,
‘“CHALLENGER” REPORTS’ 100

12 _Rhabdopleura normani._ AFTER LANKESTER,
‘CONTRIBUTIONS TO OUR KNOWLEDGE OF RHABDOPLEURA
AND AMPHIOXUS’ 112

13 A SINGLE POLYPIDE OF _Rhabdopleura normani_. AFTER
LANKESTER, _tom. cit._ 114

14 _Bathyteuthis abyssicola._ AFTER HOYLE,
‘“CHALLENGER” REPORTS’ 121

15 _Bathynomus giganteus._ AFTER FILHOL, _tom. cit._ 131

16 _Euphausia latifrons._ AFTER SARS, ‘“CHALLENGER”
REPORTS’ 134

17 _Bentheuphausia amblyops._ AFTER SARS,
‘“CHALLENGER” REPORTS’ 134

18 _Polycheles baccata._ AFTER SPENCE BATE,
‘“CHALLENGER” REPORTS’ 136

19 _Colossendeis arcuatus._ AFTER FILHOL, _tom. cit._ 141

20 _Hypobythius calycodes._ AFTER MOSELEY,
‘“CHALLENGER” REPORTS’ 145

21 _Melanocetus Murrayi._ AFTER GÜNTHER,
‘“CHALLENGER” REPORTS’ 156

22 _Saccopharynx ampullaceus._ AFTER GÜNTHER,
‘“CHALLENGER” REPORTS’ 164

THE FAUNA OF THE DEEP SEA