INTRODUCTORY. 



xix 



111 pursuance of this, we found it desirable to enlarge upon the 

 descriptive chapters in our later treatment. 



Not in all the volumes, but in some, appendixes appear, or 

 introductory chapters upon the geology of the areas, and other 

 subjects which appeared to us desirable. 



The third volume (1890) — The Birds of lona and Mull — can 

 only be looked upon — as we indicated in the Preface — as a " relief 

 volume," not in absolute plan or keeping with the rest, but as a 

 contribution by a very able field-naturalist and observer; and as 

 such I hope it has been accepted. 



In our next volume (Orkney) we returned to the plan, and in 

 it we desire to admit the incompleteness of our treatment of the 

 Fishes, as indeed we also do as regards this part of our work in all 

 the volumes; and we admit the desirability of some modifications 

 suggested by our reviewers. The Bibliography in this volume repre- 

 sents a fairly complete r6sum6 of previous information. But biblio- 

 graphy, when completed, will some day show how impossible it 

 would have been to include everything within the space allowed in 

 a single square 8vo volume. This is quite another undertaking. 



In our fifth volume the same plan is followed, and the notes by 

 the late Mr. Graham in vol. iii. were incorporated so far as considered 

 necessary. But there still remains a considerable filling in of detail 

 for the island of Mull, and also for the area of Argyll, upon which 

 there is little doubt much of interest remains untold. Some of this 

 has been attended to since publication, a considerable amount of 

 material having been accumulated to date of 1906. It was indicated 

 then also that a complete bibliography relating to our subject may at 

 some future time be fully compiled and done justice to {vide Preface, 

 p.vii). 



The usual definitions of the boundaries and descriptions of the 

 area received attention, and occupied — as these generally do — a con- 

 siderable portion of the introductory chapters. 



In the next two volumes of the series (Moray) a departure 

 was made, in that we saddled our patient subscribers with a double 

 yoke of volumes. Perhaps we may be forgiven — at least in part — 

 owing to the great size of this area, and also because we had to 

 rectify our initial mistake in our first volume, in order to complete 

 this natural area, and bring up to date the fauna of that part of the 



