The county of Cambridgeshire cannot be said to have a rich fauna so far as the Mammalia are concerned, and although the number of species actually recorded might compare favourably with those in other counties, yet the number of those species which may be said to be truly indigenous is comparatively small.

The absence of large tracts of wood is probably no small factor in this scarcity; most of the larger animals, such as the Badger, the Marten and the Fox–as well as many species of bats and smaller rodents–being only able to maintain their existence by the shelter and food afforded them in a woodland county.

Roughly speaking, the northern half of Cambridgeshire is flat and woodless, with a few elevations, such as the Isle of Ely, standing up from the surrounding level of the reclaimed Fenland; towards the south and west the county becomes more undulating and wooded, but the district is too small for many rarities to have been found or recorded from it.

The scarcest mammal to which we can lay claim is a bat (Myotis myotis), a specimen of which was captured alive about fifteen years ago at Girton. This species, abundant on the Continent, is only known in England, to which it must be considered an extremely scarce straggler, from this and one previous example taken in the British Museum grounds at Bloomsbury.

The number of species of Myriapods found in Great Britain is not a very large one. This may in part be due to the alterations that have been made in recent times in the classification of the group. The two authors who have done most work in the enumeration of the British species are Newport and Leach. At the time when they wrote, the total number of species known was not a quarter of those known at the present day; and the characters which these writers used in the determination of their species were not the same as those which are utilized in more modern times. This renders it a very difficult matter to come to a conclusion as to how far the species known in this country extend on the Continent, and whether we have in this country any species altogether peculiar to it.

Though the range of species both of Chilopods and Diplopods is a wide one in one way, yet in another way they are extremely local. This seeming contradiction is due to the fact that one kind of habitat suits certain species and they are rarely to be found in a place where the circumstances are different. This is so much the case that Dr Karl Verhoeff arranged the Diplopoda according to their habitat; thus: (1) Diplopods living on heavy land; (2) on sandy land; (3) under stones; (4) on leaves; (5) under bark; (6) on plants; (7) cave Diplopods; (8) Alpine Diplopods; (9) foreign Diplopods.

It is the object of this Guide to afford help to those students of Natural History who desire to make observations in the Cambridgeshire district.

It is our pleasant duty to acknowledge the assistance we have received from many willing helpers in preparing the Guide.

In the first place we wish to tender thanks to the various authorities on the different subjects who have without remuneration written the articles included in the book.

To the Editors and Publishers of the Victoria History of the Counties of England we owe our thanks for the article on the Vertebrate Palæontology of the County which was written by Mr R. Lydekker for the County History of Cambridge, and is here allowed to appear in advance. We are also indebted to them for the use of other materials acknowledged in the body of the work.

The Geological Map of the County was kindly made by Mr H. H. Thomas, M.A., of H.M. Geological Survey. Our thanks are due to him and also to the Controller of H.M. Stationery Office, who has permitted us the use of the topographical details inserted on the map of H.M. Ordnance Surveys (4 miles to the inch), and of the Geological lines which are taken from the maps of H.M. Geological Survey. The map has been prepared at the Office of the Ordnance Surveys, Southampton.

The county of Cambridge is about fifty miles in length from north to south, and its greatest breadth from east to west is about thirty miles; it occupies an area of eight hundred and sixty square miles. The greater part of the county is drained by the river Ouse and its tributaries, of which the Cam is the principal, while the northern part is traversed by a portion of the Nen and its tributaries.

Along part of its course the old Ouse river ran in a direction somewhat north by east from St Ives, past Ely, dividing the county into two portions, of which the northern is almost entirely composed of fenland, while the southern is largely occupied by more elevated ground.

In accordance with its geological structure the county is divisible into three important areas, and two minor ones. The former consist of (i) the chalk tract which lies to the east of the Cam between the southern part of the county and Waterbeach, (ii) the curiously dissected plateau which occupies the south-western part of the county between the valleys of the Cam and Ouse, and (iii) the Fenland of the northern part of the county. The minor tracts consist of the alluvial belts which border the Cam and its tributaries and the ridges of old river gravels; and a small plateau topped by gravels which occupies the country around Fordham, Chippenham, and Newmarket.

The object of this short account of the Flora of the Cambridge district is not to give a list of localities, but rather to direct the attention of the reader to the vegetation as a whole. In the first portion of the paper will be found a short analysis of our flora and an attempt to explain the present distribution, that is, the Cambridge flora in relation to that of the rest of England.

The remainder of the paper is occupied with an account of the plant associations found in the district or the local flora.

By the Cambridge district is meant that portion of the county which is within easy reach of the town either by train or bicycle–that is to say, it consists of the whole of South Cambridgeshire, a small strip of North Hertfordshire, a corner of Essex and the western border of Suffolk.

Watson classified British plants according to their distribution in the Island. Those that were generally distributed he called British, those that were abundant in the south and tended to disappear towards the north he called English. He found that there were certain plants restricted to the East of England, to which he gave the name Germanic, not thereby implying that they had their origin in Germany, but using the word simply as a name to signify that they were plants found on that side of England which bordered on the German Ocean.

Cambridgeshire, although small, possesses a remarkably rich and varied Entomological fauna, due to a considerable variety of country being included in the long straggling shape of the county.

Of real fen-land very little remains; the whole of the northern part of the county, the centre of that large tract of Fens which extends into north Huntingdonshire, Lincolnshire, Norfolk and Suffolk, has been reclaimed, and is now, with the exception of small isolated parts, agricultural land of a somewhat uninteresting character, at least from the entomologist's point of view. The Fens of Horningsea, Bottisham, Swaffham, and Burwell, immediately north of Cambridge, have also been reclaimed in the last thirty or forty years, and although a semi-wild state is maintained in parts where turf-digging is carried on, the greater part is cultivated land, and but few of the interesting insects which were to be found there in the middle of last century remain. About 300 acres of sedge fen at Wicken alone survives in something of its original state; a succession of bad hay seasons has however raised the value of sedge and such rough fodder as the Fen produces, and a considerable amount of cutting has been done, to facilitate which a lot of bushes have been “stubbed” up.