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VII. — The Rotifera of the Scottish Lochs. By James Murray. Including 

 descriptions of New Species by C. F. Rousselet, F.R.M.S., and D. Bryce, Esq. 

 Communicated by Sir John Murray, K.C.B. (With Six Plates.) 



(MS. received March 5, 1906. Read May 28, 1906. Issued separately June 14, 1906.) 



Introduction. 



A necessary preliminary to the study of the complex problems involved in the 

 biology of lakes is to ascertain the facts. The collection of the bathymetrical data was 

 begun many years ago by Sir John Murray and Mr Pullar, and is nearing com- 

 pletion under the Lake Survey. The next thing is to take a census of the inhabitants. 

 This we are now trying to do by compiling lists of the animals and plants living in the 

 lakes. The study of the problems after the data are collected falls outside the province 

 of a lake survey, and within that of some permanent biological station. This present 

 compilation is one step in the accumulation of the facts. 



This list of Rotifera observed in the Scottish lochs makes no claim to be exhaustive. 

 A glance over it will show, to those competent to judge, where it is deficient, and how 

 unequal is the treatment of the three orders represented. Records by other observers are 

 not induded. Gosse records many Scotch Rotifers, some of them lacustrine ; Messrs W. 

 and G. S. West, in their plankton papers, Calman (1 1), and others, in various publications, 

 have made mention of limnetic Rotifers. Messrs Scott and Lindsay (47) give a list of 

 nearly 100 species from one small loch. To Hood, more especially, one of the pioneers 

 of the study of the Rotifera, who has brought to our knowledge so many beautiful and 

 interesting forms, must be credited the discovery of a great many species in Scottish 

 lochs. Mr Hood's records, however, are often unlocalised, being set down simply 

 as from lakes and ponds in Scotland ; and inasmuch as the list, even with his and 

 other workers' records included, would still be far from exhaustive, it is judged best 

 to make this simply a list of species observed by the Lake Survey, a contribution 

 to the knowledge of lake Rotifera. 



The compiler of the list having made a special study of one order, the Bdelloida, 

 that order is treated with greater fulness than the others ; the Rhizota and Ploima 

 might easily be added to if qualified naturalists were to make a special study of our lakes. 

 In those orders a great many more species than are here recorded were actually seen, 

 but many could not be identified. A fourth order, the Scirtopoda, did not occur at all 

 in our collections. 



The number of Rotifera now known to science is very great. The 400 species, or 



thereabouts, known to Hudson and Gosse (22) in 1889 have been continuously added 



to since, and probably at the present time more than twice as many are on record. No 

 TRANS. ROY. SOC. EDIN., VOL. XLV. PART I. (NO. 7). 21 



