CONTENTS. 



CHAPTBE I. 



INTRODUCTION. 



The Question of a Bathymetrical Limit to Life. — The general Laws which 

 regulate the Geographical Distribution of Living Beings. — Professor 

 Edward Forbes' Investigations and Views. — Specific Centres. — Repre- 

 sentative Species. — Zoological Provinces. — Bearings of a Doctrine of 

 Evolution upon the Idea of a ' Species/ and of the Laws of Distribution. 

 — The Circumstances most likely to affect Life at great Depths : Pres- 

 sure, Temperature, and Absence of Light , Page 1 



CHAPTER 11. 



THE CRUISE OP THE 'LIGHTNING.' 



Proposal to investigate the Conditions of the Bottom of the Sea. — Sugges- 

 tions and Anticipations. — Correspondence between the Council of the 

 Royal Society and the Admiralty. — Departure from Stornoway. — The 

 Fseroe Islands. — Singular Temperature Results in the Fseroe Channel. — 

 Life abundant at all Depths. — Brisinga coronata. — HoUenia carpenteri. 

 — General Results of the Expedition Page 49 



Appendix A. — Particulars of Depth, Temperature, and Position at the 

 various Dredging Stations of H.M.S. 'Lightning,' in the Summer of 

 1868 ; the Temperatures corrected for Pressure Page 81 



CHAPTER III. 



THE CRUISES OP THE 'PORCUPINE.' 



The Equipment of the Vessel. — The first Cruise, under the direction of Mr. 

 Gwyn Jeffreys, off the West Coast of Ireland and in the Channel 

 between Scotland and Rockall. — Dredging carried down to 1,470 fathoms. 



