702 REPORT — 1895. 



of investigation wliicli require an extended knowledge of, or at least make use of the 

 results obtained from, various distinct subjects. One of tbese is oceauograpby, 

 another is bionomics, which I have referred to above, a third is the philosophy of 

 zoology, or all those studies which bear upon the theory of evolution, and a fourth 

 is the investigation of practical fishery problems— which is chiefly an application 

 of marine zoology. Of these four subjects — which while analytic enough in the 

 detailed investigation of any particular problem, are synthetic in drawing together 

 and making use of the various divergent branches of zoology and the neighbouring 

 sciences — oceanography, bionomics, and the fisheries' investigation, are most closely 

 related, and I desire to devote the remainder of this Address to the consideration 

 of some points in connection with their present position. 



Dr. Murray, in a few only too brief paragraphs at the end of his detailed sum- 

 mary of the results of the ' Challenger ' Expedition, which I have alluded to above, 

 states some of the views, highly suggestive and original, at which he has himself 

 ai'rived from his unique experience. Some of his conclusions are very valuable 

 contributions to knowledge, which will no doubt be adopted by marine zoologists. 

 Others, I venture to think, are less sound and well founded, and will scarcely stand 

 the test of time and further experience. But for all such statements, or even sug- 

 gestions, we should be thankful. They do much to stimulate further research ; 

 they serve, if they can neither be refuted nor established, as working hypotheses ; 

 and even if they have to be eventually abandoned, we should bear in mind what 

 Darwin has said as to the difference in their influence on science between erroneous 

 facts and erroneous theories. 'False facts are highly injurious to the progress of 

 science, for they often endure long ; but false views, if supported by some evidence, 

 do little harm, for everyone takes a salutary pleasure in proving their falseness ; and 

 when this is done, one path towards error is closed, and the road to truth is often 

 at the same time opened.' ' 



With all respect for Murray's work, and fully conscious of my own temerity in 

 venturing to differ from one who has had such an extended experience of the sea 

 and its problems, I am constrained to express my disagreement with some of his 

 conclusions. And I am encouraged to do so by the belief that Murray will rightly 

 feel that the best compliment which zoologists can pay to his work is to give it 

 careful, detailed consideration, and discuss it critically. He will, I am sure, join 

 me in the hope that, whether his views or mine prove the false ones, we may be 

 able, by their discussion, to close a ' path towards error,' and possibly open ' the 

 road to truth.' 



One of the points upon which Murray lays considerable stress, and to the 

 elaboration of which he devotes a prominent position in his ' General Observations 

 on the Distribution of Marine Organisms,' is the presence of what he has called a 

 ' mud-line ' around coasts at a depth of about one hundred fathoms. It is the 

 point ' at which minute particles of organic and detrital matters in the form of 

 mud begin to settle on the bottom of the ocean.' He regards it as the great 

 feeding ground, and a place where the fauna is most abundant, and from which 

 there have hived off, so to speak, the successive swarms or migrations which have 

 peopled other regions — the deep waters, the open sea, the shallow waters and the 

 estuaries, fresh waters, and land. Murraj' thus gives to his mud-line both a 

 present and an historic importance which can scarcely be surpassed in the economy 

 of life on this globe. I take it that the historic and the presenfimportauce stand 

 or fall together — that the evidence as to the origin of faunas in the past is derived 

 from their distribution at the present day, and lam inclined to think that Murray's 

 opinion as to the distribution of animals in regard to the mud-line is not entirely 

 in accord with the experience of specialists, and is not based upon reliable statistics. 

 Murray's own statement is - : — ' A depth is reached along the Continental shores 

 facing the great oceans immediately below which the conditions become nearly 

 uniform in all parts of the world, and where the fauna likewise presents a great 

 uniformity. This depth is usually not far above nor far below the 100 -fathom 



' Darwin, The Descent i<f Man, 2nd edit., ] 882, p. COG. 

 - Challenger Expedition JSumnuiry, vol. ii. p. 1433. 



