334 Part III. — Eighth Annual Report 



No. VIII.— THE INVERTEBRATE FAUNA OF INLAND WATERS. 

 —I. REPORT ON LOCH COULTER AND THE COULTER 

 BURN, STIRLINGSHIRE. By Thomas Scott, F.L.S. 



The systematic investigation of the fauna of fresh water lakes, 

 especially in those of great depths, has in recent years been largely under- 

 taken on the Continent, by Forel, Pav'esi, Fol, and a number of other 

 investigators ; but in this country comparatively little has yet been done 

 on this subject. It is now proposed to make, from time to time as 

 opportunity allows, a biological and physical investigation of the great 

 Scottish lochs and inland waters, which cannot fail to be of interest in 

 regard to the food-fishes which inhabit them, and will also incidentally throw 

 light upon many other questions of scientific interest. The physical, and to 

 some extent the biological, conditions of some of the West Coast lochs have 

 been inquired into by Dr John Murray, the Director of the Challenger 

 Commission ; and Mr J. S. Grant Wilson a year or two ago made a 

 physical examination of the lochs in Perthshire. A comparison will be 

 made of the fauna of lochs, which have been in recent geological times 

 cut off from the sea, with the fauna of typical inland lochs, and with that 

 of those where there now occurs an admixture of sea water. The nature 

 and distribution of the invertebrate organisms in the waters of very deep 

 lochs will also be investigated. It is well known that marked differences 

 exist between the trout and other edible fishes of many lochs. This 

 inquiry by determining the main food of these fishes may lead to useful 

 measures being recommended. 



In compliance with instructions received, I began in June 1889 an 

 investigation of the invertebrate fauna — especially the Crustacea and 

 Mollusca — of Loch Coulter, and its effluent, the Coulter Burn. 



Loch Coulter is situated in a natural hollow about 300 yards to the 

 east of the Stirling and Kilsyth Road, and nearly midway between these 

 two places. It lies almost due east and west ; its greatest length is about 

 1100 to 1200 yards, its greatest breadth 600 to 700 yards, and it has a 

 somewhat quadrangular outline. From the peculiar physical conditions 

 of the district in which this loch is situated, only a few ditches drain 

 into it, but one or more springs are reported to exist somewhere within 

 its area. The Coulter Burn is the only outlet for the water of the loch. 

 It takes its rise from the north-west corner, and flows east and north by 

 a rather circuitous route, passing on its way through the well-known 

 Hovvietoun Fisheries and Goldenhoof Dam, and joins the Bannock 

 Burn a little to the south of the site of the historical battle of that name. 



Sir J. Ramsay-Gibson-Maitland, Bart, kindly gave me information 

 and advice, which were of the greatest value to me in making arrange- 

 ments as to the manner in which the investigation should be made. 



As I had to return to Edinburgh, in order to continue my investiga- 

 tions on the ' Garland,' it was decided, that as soon as arrangements 

 could be made for proceeding with the work, my son, Mr Andrew Scott, 

 should take my place in carrying on the proposed investigations, which 

 he did on 12th June. In order to enable him to carry out the examina- 

 tion as carefully and accurately as possible, I drew up for his guidance 

 a plan of work, dividing the district into sections, and instructing him to 

 xamine each separately and consecutively, and to take notes of the 

 organisms observed and collect samples of material. My son completed 

 his investigations on the 22nd of June, having examined Loch Coulter 



