182 ANNIVERSARY ADDRESS 



'Blake,' invented a cylinder or machine, called the "gravitating 

 trap," which completely answered the purpose of collecting at any 

 jiarticular depth the animals which occurred there. Professor 

 Alexander Agassiz, in his communication to the Superintendent of 

 the Survey made last August, and now published, records the 

 experiments thus made, and says that they " appear to prove 

 conclusively that the surface fauna of the sea is really limited 

 to a comparatively narrow belt in depth, and that there is no 

 intermediate belt, so to speak, of animal life between those living 

 on the bottom, or close to it, and the surface pelagic fauna." 



I am not aware that any deep-sea animals adopt or avail them- 

 selves of the same means that oceanic or land animals use for 

 purposes of protection and concealment, chiefly by coloration or by 

 what has been termed " mimicry." Many cases of this kind are 

 known to occur in birds, fishes, molluscs, Saljxs, insects, crabs, 

 shrimps, and worms. 



None of the animals whose remains are found in geological 

 formations older than the Pliocene or latest of the Tertiary strata 

 have yet been detected in any exploring expedition. The late 

 Professor Agassiz and Sir Wyville Thomson were disappointed in 

 their enthusiastic expectation of finding ammonites, belemnites, 

 and other old-world fossils in a living state. I have dredged 

 Miocene fossils on the coasts of Guernsey and Portugal, the latter 

 at considerable depths ; but they were petrifactions, and must have 

 come from some fossiliferous formation in the adjacent land, or 

 perhaps in the sea-bed. 



Sir Wyville Thomson, in his ' Report of the Scientific Results of 

 the Yoyage of H.M.S. " Challenger," ' has expressed his opinion as 

 to the doctrine of evolution, that " in this, as in all cases in which 

 it has been possible to bring the question, however remotely, to the 

 test of observation, the character of the abyssal fauna refuses to 

 give the least support to the theory which refers the evolution of 

 species to extreme variation guided only by natural selection." 

 I cannot understand how either "natural selection" or "sexual 

 selection " can affect marine invertebrate animals, which have 

 no occasion to struggle for their existence and have no distinction 

 of sex. 



4. Food. 



The late Professor Sars, in his remarks on the distribution of 

 animals in the depth of the sea, asks: " Whence do animals that 

 live at depths far below the limits of vegetation obtain their 

 food ? " Bronn, Wallich, Wyville Thomson, and others have en- 

 deavoured to answer this question ; but I do not think the problem 



