CITELLUS 723 



in California^ and elsewhere have thus become numbered 

 among the worst mammalian pests, inflicting enormous losses 

 upon agriculture. These teeming Souslik populations have 

 shown themselves to be liable to plague infection, and in this 

 respect they constitute a very grave peril to the public health 

 in many regions. 



Fossil remains of Ciiellus were first discovered in the 

 European Pleistocene by Kaup, who described {Oss. Foss. 1839, 

 p. 112, Plate XXV., Figs. 3 and 4) a beautifully preserved 

 skull, which was at first believed to have come from the 

 Miocene Dinotherium Sand of Eppelsheim ; this specimen 

 formed the basis of Kaup's Spermophilus superciliosus. In 

 1842, Desnoyer and Provost found abundant Souslik remains, 

 which they referred to C. citellus, in the Pleistocene bone- 

 breccia of the caves and fissures of Montmorency. Dr Hugh 

 Falconer in 1859 was the first to detect the genus among 

 British fossils, and in his posthumous PalcBontological Memoirs 

 (vol. ii., p. 472, 1868) two lower jaws from the bone-caves 

 of the Mendip Hills, and another from the brickearth at 

 Fisherton near Salisbury, are described and figured. To the 

 Mendip specimens Dr Falconer gave the name Spermophilus 

 erythrogenoides, but recent study tends to show that this 

 name must be treated as a synonym of superciliosus. Since 

 these earliest discoveries, remains of Sousliks have been found 

 in numerous British and Continental deposits of late 

 Pleistocene age. Many specimens were obtained by Dr 

 Blackmore from the Fisherton deposit, while other observers 

 have found remains in the later deposits of the Middle Terrace 

 of the Thames at Crayford and Erith, in the fissure deposits 

 at Ightham, Kent, and in the Langwith Cave in Derbyshire 

 (Cheadle, Proc. W. London Sci. Assoc, i, p. 7, 1876; Newton, 

 Quart. Journ. GeoL Soc, 50, 1894, pp. 94 and 55, and 1899, 

 p. 422 ; Mullens, Derbyshire Archceol. Nat. Hist. Soc. Journ., 

 j'913, p. 15.) In 1882 Mr E. T. Newton described [Geol. Mag. 

 [ii.] ix., p. 51) some fragmentary remains found by Mr Clement 

 Reid in the "Arctic Freshwater Bed "at Mundesley, Norfolk, 



' A most valuable account of the Ground Squirrels of California has been published 

 recently by J. Grinnell and J. Dixon {Monthly Bulletin of the State Commission of 

 Horticulture, Sacramento, vol. vii., pp. 597-708, 1919). 



