706 REPORT— 1895. 



Scott, F.L.S., and Mr. I. C. Thompson, F.L.S. — and tliey all agree in stating that, 

 although interesting and peculiar, the Copepoda and Ostracoda from the deep mud 

 are not abundant either in species or in individuals. In answer to the question 

 which of the three regions (1) the littoral zone, (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 replied the middle region from to 20 fathoms, which 

 is the Laminarian zone and the upper edge of the Coralline. Professor Brady 

 assures me that nearly every other kind of bottom and locality is better than mud 

 for obtaining Ostracoda. Mr. T. Scott considers that Ostracoda are most abundant 

 in shallow water, from 5 to 20 fathoms. He tells me that as the result of his 

 experience in Loch Fyne, where a great part of the loch is deep, the richest fauna 

 is always where banks occur, coming up to about 20 I'athoms, 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 had great experience in collecting, considers that the richest fauna is 

 usually at about 20 fathoms. My own experience in dredging in Norway is the 

 same. In the centre of the fjords in deep water on the mud there are rare forms, 

 but very few of thenj, while in shallower water at the sides, above the mud, on 

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



Probably no gi'oup of animals in the sea is of so much importance from the 

 point of view of food as the Copepoda. They form 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. Con- 

 sequently, I have inquired somewhat cai'efuUy into their distribution in the sea, 

 with the assistance of Professor Brady, Mr. Scott, and Mr. Thompson. These 

 experienced collectors all agree that Copepoda are most abundant, both as to species 

 and individuals, close round the shore, amongst seaweeds, or in shallow water in 

 the Laminarian zone over a weedy bottom. Individuals are sometimes extremely 

 abundant on the surface of the sea amongst the plankton, or in shore pools 

 near high water, where, amongst Enteromorpha, the Ilarpacticidoe swarm in im- 

 mense profusion ; but, for a gathering rich in individuals, species, and genera, the 

 experienced collector goes to the shallow waters of the Laminarian zone. In 

 regard to the remaining, higher, groups of the Crustacea my friend, Mr. Alfred 

 O. Walker, tells me that he considers them most abundant at depths of to 20 

 fathoms. 



I hope no one will think that these are detailed matters interesting only to 

 the collector, and having no particular bearing upon the great problems of biology. 

 The sea is admittedly the starting-point of life on this earth, and the conclusions 

 we come to as to tlie distribution of life in the different zones must form and 

 modify our views as to the origin of the faunas — as to the peopling of the deep 

 sea, tile shallow waters, and the land. Murray supposes 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 Professor Moseley considered 

 the pelagic or surface life of the ocean to be the primitive life from which all 

 the others have been derived. Professor W. K. Brooks ' considers that there was 

 a primitive pelagic fauna, consisting of the simplest microscopic plants and 

 animals, and ' that pelagic life was abundant for a long period during which the 

 bottom was uninhabited.' 



I, on the other hand, for the reasons given fully above, consider that the 

 Laminarian zone close to low-water mark is at present the richest in life, that it 

 probably has been so in the past, and that if one has to express a more definite 

 opinion as to where, in Pre-Cambrian times, life in its simplest forms first appeared, 

 I see no reason why any other zone should be considered as having a better claim 

 than what is now the Laminarian to this distinction. It is there, at present at 

 any rate, in tlie upper edge of the Laminarian zone, at the point of junction of sea, 



' The genus Salpa, 1893, p. 156, kc. 



