464 
MR. W. E. HOYLE ON THE DEEP-WATER 
For this purpose use must be made of the distributional notes 
appended to each species in the list. According to this infor- 
mation the species fall into three categories. The first contains 
those which range from Scandinavia to the Mediterranean, or 
even more widely still ; these may be termed, for the present 
purpose, “ Wide-spread ” species. The second consists of those 
forms which are common to the Arctic and Scandinavian waters, 
and hence may be termed “ Northern whilst the third is made 
up of species which may be called “ Southern,” as they extend 
to the Mediterranean or the African coast. 
The following Table shows the numbers of species of the 
various classes of animals which belong to each of these cate- 
gories : — 
Wide-spread 
Species. 
Northern 
Species. 
Southern 
Species. 
Pisces 
23 
17 
2 
Tunicata 
4 
5 
Mollusca and 1 
Brachiopoda ... J 
zz 
o 
Polyzoa 
20 
5 
1 
Crustacea 
32 
41 
5 
Vermes 
3 
3 
Echinodermata 
10 
13 
2 
Coelenterata 
9 
4 
9 
Totals 
147 
110 
22 
From these figures it appears that the major part of the fauna 
is composed of species which are dispersed more or less widely 
over the north temperate regions of the globe, whilst the smaller 
half is very unequally divided between the northern and southern 
species, the former being five times as numerous as the latter. 
In only one division of animals (the Coelenterata) do the southern 
forms predominate over the northern, and this subkingdom has 
been hitherto very inadequately investigated iu the Clyde area. 
The depth of 20 fathoms as limiting what might be considered 
the deep-water fauna iu the Clyde sea-area was selected not 
from any preconceived idea as to its significance, but because it 
Avas convenient for practical purposes, and because it was appli- 
cable to all the lochs, the extreme depth of the Gareloch, Avhich 
