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XXIV. — Scottish Tardigrada, collected by the Lake Survey. By James Murray. 

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



(MS. received January 2, 1907. Read February 4, 1907. Issued separately May 20, 1907.) 



Introduction. 



In 1905 there was published an account of the Tardigrada collected in the Scottish 

 Lochs by the Lake Survey (6). At that date we were able to name 21 species. 

 The subsequent work of the Survey has enabled us to add a number of species .to 

 the list. 



Moreover, the wanderings of the members of the Survey over every part of 

 Scotland offered an excellent opportunity for the study of the whole Tardigrade Fauna. 

 A recent journey to the Orkney and Shetland Islands added much of interest to our 

 knowledge of Tardigrada, though few of the species found were lacustrine. The work 

 of Mr Wm. Evans in the basin of the Forth has also added much of value to our 

 records of Tardigrada (7), (10). 



Considering the large number of species now collected from all parts of the country, 

 it is thought desirable to bring together all that is known about Scottish Tardigrada, in 

 the hope that such a resume will assist the further study of this group of animals. 



The Tardigrada are now being found to be much more numerous than was long 

 thought. A great many of the earlier species are very insufficiently described ; and the 

 more it appears that species are numerous, the more doubt attaches to the earlier 

 descriptions. Some of these are doubtless compounded of the characters of various 

 species which were confounded together. Many of the most important characters were 

 neglected, under the impression that they were not sufficiently stable : the pharynx, 

 with its system of rods, for instance, was hardly regarded before Richters, while I see 

 no reason to suppose that the number and form of these rods is any less constant than, 

 say, the dentition of Vertebra ta. 



All the Tardigrada yet found in Scotland have their ordinary habitat among moss. 

 They appear to be generally indifferent to the situation of the moss, as the same species 

 may be found alike among permanently moist moss, and among moss which is only 

 intermittently moist. No doubt there are some exceptions, and certain species may affect 

 always certain situations. Professor Richters remarks that the degree of coloration 

 of M. oberhduseri appears to depend on the exposure of the wall where they are found. 



Some kinds are found in the mud of ponds and lakes when no moss may be present, 

 but those same kinds are commoner among moss. 



TRANS. ROY. SOC. EDIN., VOL. XLV. PART III. (NO. 24). 91 



