200 



Part III. — Seventeenth Annual Report 



Drepanothrix dentata (Euren) was also obtained in the Dim Loch, as 

 well as in Loch Arklet, Loch Achray, and Loch Doon. This species 

 appears to have a wide distribution in Scotland. 



Acantholeberis curvirostris, 0. F. Midler.— This also was observed in 

 the Dhu Loch and in Loch Arklet; but these are the only two of the 

 present series of lochs in which it occurred. 



LyNCBID/E. 



Camptocercus rectirostris, Schoedler. — The Camptocercus that has been 

 observed in four of the lochs under consideration appears to be the form 

 that has been described by Schoedler under the name of Camptocercus 

 rectirostris, and which is referred to under that name by Herrick in his 

 "Crustacea of Minnesota." Figure 56, Plate VII., represents one of the 

 specimens from Loch Doon, the post-abdomen of which is represented by 

 figure 57. The figure of the post-abdomen of the Camptocercus in Dr. 

 Baird's classical work agrees very closely with that of the form described 

 by Schoedler. In this form the spiniferous margin of the post-abdomen 

 slopes away gradually from the base of the claw ; but in the form which 

 seems to be generally considered as the Lynceus macrurus of 0. F. Miiller 

 (now Camptocercus macrurus), the post-abdomen is of moderate depth 

 throughout, the margins towards the claw are nearly parallel with each 

 other, and the slope at the base of the claw is abrupt or nearly subtruncate. 



Leydigia quadrangularis, Ley dig. — This is a rare Cladoceran in Scot- 

 land, though it appears to have a fairly wide distribution. Forfar Loch is 

 the only loch of the present series in which it was obtained. A few years 

 ago I had the privilege of submitting specimens of this form to Professor 

 G. O. Sars, who confirmed the identification of the species. In this form 

 the terminal claw of the post-abdomen is furnished near the base with a 

 distinct, though small, spinule. Figures of the species are published in 

 Part III. of the Ninth Annual Report of the Fishery Board for Scotland. 



Alona tenuicaudis, G. 0. Sars. — This also is comparatively a rare or local 

 species. It was observed only in Duddingston Loch, but it occurred in three 

 out of the five gatherings from that loch, and was frequent in two of them. 

 The post-abdomen in this species somewhat resembles that of Alonopsis, 

 but its armature is very different. 



Alona intermedia, G. 0. Sars. — The Lynceid, which I have described 

 under the name of Alona neglecta* appears to be the Alona intermedia 

 of G. O. Sars ; while the Lynceid recorded as Alona intermedia from 

 various parts of Scotland t and England X is the Alona rectangula of G. 

 O. Sars. Alona intermedia (A. neglecta, mihi) occurred in four of the 

 lochs of the present series, but was scarce in all of them. It is a small 

 species and readily overlooked, and may therefore appear rarer than it 

 really is. 



Alona rustica, T. Scott. — It appears from recent investigations that this 

 is a widely distributed species in Britain. It has been obtained in Shetland, 



* Thirteenth Annual Report of the Fishery Board for Scotland, Part III., p. 189, 

 Plate V., figures 4, 18. 



f Annual Reports of the Fishery Board for Scotland, Part III., 1895, p. 188 ; 1896, 

 p. 237 ; 1897, p. 333 ; and 1898, p. 252. 



X "The Entomostraca of Epping Forest." by D. J. Scourfield, in The Essex 

 Naturalist, Vol. X., p. 319, 1898. 



