14 



Part III. — Seventeenth Annual Report 



The Invertebeate Fauna of the Inland Watees of Scotland. 



For a few years past investigations have been carried on by Mr. 

 Thomas Scott, F.L.S., on the invertebrate fauna of a number of 

 Scottish lochs, and in the present Eeport the results are given of 

 the investigation of a number of them, including Loch Lomond, 

 Loch Arklet, Loch Katrine, Loch Achray, Loch Leven, Loch Doon, 

 and Lochs Ness, Oich, and Lochy. One object of the enquiry was 

 to ascertain the effect produced on the invertebrate fauna by the 

 changes incident to the different seasons of the year, and the 

 examination of each loch was made at intervals, the temperature 

 and other physical conditions being also noted. The number of 

 species obtained was 132, of which 115 belong to the Crustacea 

 and 17 to the Mollusca ; and the invertebrate fauna of some of the 

 lochs, as Loch Lomond, Loch Leven, Loch Doon, and Loch Achray, 

 was found to be much richer in species than others. Notes are 

 appended on the seasonal distribution of the organisms in each 

 loch, on the local distribution of certain species, and on the varia- 

 tions in the forms of Daphnia. 



In another paper Mr. Scott describes the collections of micro- 

 crustacea obtained from the Firth of Clyde and the Moray Firth, 

 including a number of new species and two new genera of 

 Copepoda. The paper is illustrated by a series of drawings. 



The Migeatoey Movements and Bate of Geowth of the 

 Common Guenaed. 



In a paper on this subject, by Dr. T. Wemyss Fulton, it is shown 

 that the gurnard is practically absent from the inshore waters of 

 the Firth of Forth and St. Andrews Bay during the winter months. 

 When the temperature of the bottom water inshore begins to fall 

 in the autumn the gurnards migrate to the offshore grounds in the 

 open sea, where the temperature is higher, and where they pass 

 the winter. When the temperature inshore begins again to rise, 

 usually about the end of March, gurnards reappear at the mouth of 

 the Firth of Forth ; in April, with a slightly higher temperature, 

 the influx is considerable, and it reaches its maximnm in May. It 

 is shown that the initial shoals are composed almost entirely o 

 adult gurnards, and that the migratory movement towards the 

 inshore waters is primarily associated with reproduction. Later, 

 immature and young gurnards move in in great numbers, and these 

 immature forms are the first to leave in autumn. This movement 

 appears to be dependent on the changes in the temperature of the 

 bottom water. On the other hand, in the deeper waters of the 

 Clyde and the Moray Firth, where the winter temperature is much 

 higher than in the Firth of Forth or St. Andrews Bay, gurnards 

 may be found all the year round. Tables and Diagrams are given 

 showing the proportions of adult and immature gurnards in the 

 various months, and the relations between the migratory move- 

 ments, the spawning period, and the changes in the temperature of 

 the water. 



