303 
1906-7.] Hydrachnidse collected by the Lake Survey. 
that work contains a very full synonymy, the genera and species now 
recorded are sufficiently defined for reference. 
1. Genus HYDRACHNA, Mull. 
Hydrachna globosa, de Geer. — A nymphal form was found by Mr Scour- 
field at a pond between Mallaig and Morar, June 1902. This species has 
also been found at Oban. 
2. Genus THY AS, C. L. Koch. 
Tliy as venusta, C. L. Koch. — Found by Mr Murray at Whitebridge 
Pond, April 1904. This species has also been found in the vicinity of 
Edinburgh. 
3. Genus ARRHENURUS, Ant. Dug. 
Arrhenurus, sp. — A female specimen, not yet identified, was found by 
Mr Murray in St Mary’s Loch (at a depth of 100 feet), January 1906. 
4. Genus LEBERTIA, Neuman. 
Lebertia tau-insignita, Lebert (?) — Specimens collected by Mr Scourfield 
at Morar, June 1902, and at Loch Tarff, August 1903, were identified by 
Mr Soar as Lebertia tau-insignita , Lebert. I also identified as the same 
species a specimen taken by Mr Murray from St Mary’s Loch at a depth 
of 100 feet. 
The genus Lebertia is undergoing revision by Dr Sig Tlior. From his 
“ Lebertia-studien ” it would appear that some confusion in the naming 
of species belonging to this genus has existed for a number of years, and 
that this has arisen in some measure through the name tau-insignita 
having been erroneously separated from the specific description to which 
it belonged. 
Lebertia ( Pilolebertia ) porosa, Sig Thor, var. — This specimen was found 
by Mr Murray at Loch Ness, and identified by Dr Sig Thor. This is 
a new Scottish record. 
A specimen taken by Mr Scourfield from a loch near Fort Augustus 
has not yet been identified. 
5. Genus OXUS, P. Kram. 
Oxus ovalis , Mull. — Found by Mr Scourfield at Loch Rannoch, June 
1902. I have not seen any other record of the occurrence of this species, 
in Scotland. 
