From wfisT coast of Scotland and the ieish sea. 27 



II. Clyde Sea Area. 



7. Skate Iwland-gatheriugs : (1) in 1907, (6) (3 hauls) and (7) in 1908, and (9) in 1909 



(4 hauls) 



8. Upper Loch Fyne— gatherings : (8) in 1908 (4 hauls), and (10) in 1909. 



9. Arran, Sound of Bute, etc.— gatherings : (2), (3), and (4) in 1907, (11) and (14) 



(2 hauls) in 1908, (13) in 1909, and (15) in 1910. 



III. Irish Sea. 



10. All the 58 hauls were in the one locality, 12-16 miles N.N.W. of Port Erin, Isle of 

 Man, from depths of 59 to 73 faths. 



When we examine these groups o£ Scottish gatherings from the same 

 places in different years, two conclusions become evident : — 



(1) That localities, in some cases not very far apart, difEer very 



considerably in the nature of their plankton at the same time 

 o£ year ; 



(2) That there is a constancy year after year in the nature of the 



plankton at some localities. 

 A few examples will make this clear : — 



(1) In the northern area, the hauls taken in Loch Hourn and Loch 



Nevis are on all occasions very different from those taken off 

 Ardmore in Mull, and from those taken off the Island of Canna ; 

 also those taken in the Lynn of Morven at one end of the Sound 

 of Mull differ from those taken between Mull and Ardnamurchan 

 at the opposite end. Again, in the southern series, the hauls from 

 off Skate Island, in the entrance to Loch Fyne, differ markedly 

 from those taken further south in the Sound of Bute and the 

 Firth of Clyde off Arran. 



(2) The Loch Fyne vertical hauls are always characterised by the 



abundance of large Copepoda ; the hauls off Canna and elsewhere 

 in the Sea of the Hebrides by the prevalence of Diatoms ; those 

 in the Firth of Lorn by a fine zoo-plankton, and those round 

 Raasay on the North of Skye by a much coarser zoo-plankton. 



Let us now examine some of these cases in more detail : — 

 All the vertical hauls taken in the deep hole, 95-106 faths., off Skate 

 Island at the mouth of Loch Fyne, consist of a coarse zoo-plankton (see 

 tig. 3) characterised by a very great number of the common Copepod, Calanus 

 helgolandkus. The specimens of Calanus are large, and many of them are 

 of a red colour when alive ; and associated with them are generally a few 

 EuchcBta norvegica and one or two specimens of the Schizopod Nyctvplianes 

 norvegiciis. There are also in these hauls a few smaller Copepoda (such as 

 Pseudocalanus elongatiis and Oithona similis), some Copepod eggs and nauplii, 



