SCOTTISH TARDIGRADA, COLLECTED BY THE LAKE SURVEY. 



645 



only about 1500 feet in height, might be expected, from their high latitude, to be as 

 alpine or arctic in character as much higher hills on the Mainland of Scotland, but 

 this is discounted by the very mild climate enjoyed by those northern lands. 



Ronas Hill was indeed very rich both in arctic and in peculiar species, but this 

 may be attributed rather to geographical position than to climate. Remote though 

 Shetland is from Spitzbergen and Franz Josef Land, there are numerous stepping-stones, 

 — the Faroes, Iceland, Norway, Bear Island, etc. — between them, and the peculiar 

 feature of Ronas Hill is its union of species from so many northern but isolated lands. 



The accompanying list of hill Tardigrada, numbering 23 species, shows at a glance 

 what a large proportion of arctic species there are on our hills. E. islandicus, E. 

 wendti, E. spitsbergensis, M. coronifer, M. crenulatus, M. harmsworthi — all, except E. 

 spitsbergensis (which is frequent on the Mainland of Scotland), only previously known 

 from high northern lands, if not actually within the arctic circle. And the proportion 

 of arctic species is yet higher than appears above, for M. zetlandicus, M. dispar, and 

 M. ambiguus, though only recently discovered in Scotland, are known to extend into 

 Franz Joseph Land or Spitsbergen, and Scotland is, as far as yet known, the southern 

 limit of their range. * 



List of Scottish Alpine Species. 



Echiniscus arctomys, Ehr. Stuc-a-Chroin (Evans). 

 E. mutabilis, Murray. Ben Lawers. 

 E. islandicus, Richters. Ronas Hill, Shetland. 

 E, gladiator, Murray. Ben Lawers. 



var. exarmatus, Murray. Ronas Hill, Shet- 

 land. 

 E. wendti, Richters. Ben Lawers. 

 E. spitsbergensis, Scourfield. Ben Lawers. 

 E. quadrispinosus, Richters. Ronas Hill, Shetland. 

 Milnesium tardigradum, Doy. Ward Hill, Hoy. 

 Macrobiotics oberhduseri, Doy. Ben Lawers. 

 M. zetlandicus, Murray. Ronas Hill, Shetland. 

 M. tuberculatus, Plate. Ronas Hill, Shetland. 

 M. papillifer, Murray. Ben Ledi (Evans). 



M. hufelandi, C. Sch. Ward Hill, Hoy, Ben 



Lawers. 

 M. orcadensis, Murray. Ward Hill, Hoy. 

 M. coronifer, Richters. Ronas Hill, Shetland. 

 M. crenulatus, Richters. Ronas Hill, Shetland. 

 M. harmsworthi, Murray. Ronas Hill, Shetland. 

 M. echinogenitus, Richters. Ben Lawers, Ronas 



Hill, 

 var. areolatus, Murray. Ben Lawers. 

 M. dispar, Murray. Ronas Hill, Shetland. 

 M. ambiguus, Murray. Ronas Hill, Shetland. 

 M. dubius, Murray. Ronas Hill, Shetland. 

 Diphascon chilenense, Plate. Ben Lawers. 

 D. alpinum, Murray. Ben Lawers. 



List of all known Scottish Species. 



The first list gives the distribution in Scotland, and indicates such subdivision of 

 the genera as is possible in the present state of our knowledge. Some of the groups 

 thus separated are undoubtedly natural ; others may not be so. So many are the 

 species now known that the subdivision of the two large genera Echiniscus and 

 Macrobiotics will doubtless soon be necessary, but in the meantime our knowledge is 

 too fragmentary to permit of this. 



The second list gives the world distribution so far as the data at my disposal permit. 



* M. ambiguus has been recently found in abundance, among Thamnium lemani collected by Prof. F. A. Forel, 

 at a depth of 200 feet, in the Lake of Geneva. 



