498 



NA TURE 



[September 19, 1S95 



III answer to ihe ijucslion which of the three regions (l) the 

 littoral /'line, (2) from low water to 20 fathoms, and (3) from 20 

 fathoms onwards, is richest in small free-swimming, but bottom- 

 haunting, Crustacea, they all replieil the middle region from 

 o to 20 fathoms, which is the Uiminarian zone and the upper 

 edge of the Coralline. Trof. Brady assures me that nearly every 

 ..ther kind of bottom and locality is lieltcr than mud for obtain- 

 la. Mr. T. Scott considers that Ostracoda are most 

 shallow water, from 5 to 20 fathoms. Me tells me 

 ,,.... .V- ,.it result of his exiierience in Loch Fync, where a great 

 |xirt of the loch is deep, the richest fauna is always where banks 

 occur, coming up to about 20 fothoms, and having the bottom 

 formed of sand, gravel and shells. The fauna on and over such 

 banks, which are in the Coralline zone, is much richer than on 

 the deeper mud around them. On an ordinary shelving shore on 

 the west coast of Scotland Mr. Scott, who has h.ad great 

 ex])erience in collecting, considers that the richest fauna is 

 usually at about 20 fathoms. My own experience in dredging in 

 N Tway is the same. In the centre of the fjords in deep water 

 :. lie mud there are rare forms, but ver)' few of them, while in 

 -l.il'.'.ver water at the sides, above the mud, on gravel, shells, 

 rock, and other bottoms, there is a very abundant fauna. 



Probably no group of animals in the sea is of so much im- 

 pcirtance from the point of view of food as the Copepoda. They 

 fimn a great part of the food of whales, and of herrings and 

 many other useful fish, both in the adult and in the larval 

 state, as well as of innumerable other animals, large and small. 

 Consequently, I have inquired somewhat carefully into their dis- 

 tribution in the sea, with the assistance of Prof. Brady, Mr. 

 .Scott, and Mr. Thompson. These experienced collectors all 

 that Copepoda are most abundant, both as to species and 

 iuals, close round the shore, amongst seaweeds, or in 

 ' " >'er in the Laminarian zone over a weedy bottom. 

 I ire sometimes extremely abundant on the surface of 



ngst the plankton, or in shore pools near high water, 

 wlicrc, amongst Enleromorpha, they swarm in immense profusion ; 

 b;it. for a gathering rich in individuals, s|X'cies, and genera, the 

 I ' collector goes to the shallow waters of the 



1 zone. In regard to the remaining, higher, groups 



... 1,1. V ,„^iacea my friend, Mr. Alfred O. Walker, tells me that 

 he considers them most abundant at depths of o to 20 fathoms. 

 I hope no one will think that these are detailed matters 

 interesting only to the collector, and having no particular bear- 

 ing upon the great jiroblems of biology. The sea is admittedly 

 the .starting-point of life on this earth, and the conclusions we 

 come to as to the distribution of life in the different zones must 



form : ■ ' ' '' ■ our views as to the origin ol the faunas — as to 



ihe 1 :ie deep .sea, the shallow waters, and the land. 



Murr, _ , , = that life started in Pre-Cambrian times on the 

 mud, and from there spread upwards into shallower, waters, 

 outwards on to the surface, and, a good deal later, downwards 

 to the abysses by means of the cold polar waters. The late 

 Prof. Moseley considered the pelagic, or surface life of the ocean 

 to be the primitive life from which all the others have been 

 derivc<l. Prof. W. K. Brooks (" The Cienus Salpa," 1893. p. 156, 

 i;c.) r..ii>ll.r, ihit there w.-is a primitive pelagic fauna, consisting 

 of til licroscopic plants and animals, and "that pelagic 



lift » It for a long jieriod during which the bottom was 



uninhabited." 



I. on the other hand, for the reasons given fully above, con- 



■ irian zone close to low- water mark is at 



life, that it probably has been so in the 



ts t'l express a more tiefinile opinion as to 



i.in limes, life in its simplest forips first 



M-.LS^m why any other zone should be con - 



.; u belter claim than what is now the Laminarian 



n. It is there, at present at any rate, in the 



• Laminarian zone, at Ihe point of junction of 



r. where there is a profusion of food, where the 



; <luwn by streams or worn away from Ihe land 



' <l, where the animals are able to receive the 



■if light and heat, o.xygen and food, without 



■illy to the air, ram, frost, sun, and other 



• itw litiornl zimc, it is there thai life — it 



•rowih most active, competition 



Mv, that Ihe surrounding con- 



..... ,1 1;... . ..,.1 .1...^,....^,.. ii 



"Ulwa'd^ on the surlncc. and upwards on to the shore. Pmally, 

 - ■-,51. VOL. 52] 



it is in this Laminarian zone, protably, that under Ihe stress of 

 competition between individuals and between allied species 

 evolution of new fornis by means of natural selection has been 

 most active. Here, at any rate, we find, along with some of the 

 most primitive of animals, some of thcmo.st remarkably modified 

 forms, and some of the most curious cases of minute adaptation 

 to environment. This brings us to the subject of 



BlOXO.MICS, 

 which deals with the habits and variations of animals, their 

 modifications, and the relations of these modifications to the 

 surrounding conditions of existence. 



It is remarkable that the great impetus given by Darwin's 1 

 work to biological investigation has been chiefly directed to ' 

 problems of structure and development, and not so much to 

 bionomics until lately, \ariations amongst animals in a state of 

 nature is, however, at last beginning to receive the attention it 

 deserves. Bateson has collected together, and cl.-i.ssified in a 

 most useful book iif reference, the numerous scattered observa- 

 tions on variation made by many investigators, and h;is drawn 

 from some of these cases a conclusion in regard to the dis- 

 continuity of variation which many field zoologists find it hard 

 to accept. 



Weldon and Karl Pearson have recently applied the metliods 

 of statistics and mathematics to the study of individual variation. 

 This method of investigation, in Prof. Weldon's hands, may be 

 expected to yield results of great interest in regard to the 

 influence of variations in the young animal upon the chance of 

 survival, and so upon the adult characteristics of the species. 

 But while acknowledging the value of these methods, and 

 admiring the skill and care with which they have been devised 

 and applied, I must emphatically protest against the idea which 

 has been suggested, that only by such mathematical and statistical 

 methods of study can we successfully determine the influence of 

 the environment on species, gauge the utility of specific 

 characters, and throw further light upon the origin of species. 

 For iny i>art, I believe we shall gain a truer insight into those 

 mysteries which still involve variations and species by a stuily of 

 the characteristic features of individuals, varieties, and species 

 in a living state in relation to their environment and habits. The 

 mode of work of the old field naturalists, supplemented by the 

 apparatus and methods of the modern laboratory, is, I believe, 

 not only one of the most fascinating, but also one of the most 

 profitable fields of investigation for the philosophical zoologist. 

 Such studies must be made in that modern nutconie of the grow- 

 ing needs of our science, the Zoological Station, where marine 

 animals can be kept in captivity under natural conditions, so 

 that their habits may be closely ob.served, and where we can 

 follow out the old )irecept —first, observation and reflection ; 

 then experiment. 



The biological stations of the [present day represent, then, a 

 happy union of the field work of the older naturalists with the 

 laboratory work of the comparative anatoniisi, histologisl, and 

 embryologist. They are the culmination of the ".\quarium" 

 studies of Kingslcy and Cio-S-se, and of the feeling in both 

 scientific men and amateurs, which was cxpres.sed by Ileibert 

 Spencer when he said : " Whoever at tiie seaside has not had a 

 microscope and an aquarium has yet to learn what the highest 

 pleasures of the seaside are." Moreover, I feel that the 

 biological station has come to the rescue, at a critical moment, 

 of our lalioratory worker who, without its healthy, refreshing 

 influence, is often in these latter days in peril of losing his 

 intellectual life in the weary maze of microtome methods and 

 transcendental cytology. Tlie old Circek myth of the Libyan 

 giant, Antxus, who wrestled with Hercules and regained his 

 strength each time he touched his mother earlh, is true at least 

 of the zoologist. I am sure he derives fresh vigour from every 

 direct contact with living nature. 



In our tanks and artificial pools we can reproduce the Littoral 

 and the l^iminarian zones ; we can see the methods of feeding 

 and breeding -the two most ])owerfnl factors in influencing an 

 animal. We can study mimicry, and test theories of protective 

 and warning colouration. 



The explanations given by these theories of the varied forms 

 and coUiurs of animals were first applied by such leaders in our 

 science as Bales, Wallace, and Darwin, chiefly to insects and 

 birds, but have lately been extended, by the investigations of 

 (;iard, (iarstang, Clubb, and others, to the case of marine 

 animals. I may mention very briefly one or two examples. 

 Amongst the Nudibranchiate Mollusca — familiar animals around 



