DICROSTONYX 397 
from Quedlinburg, Saxony (Hensel, of. czt. supra, p. 393); 
Eppelsheim, near Darmstadt, Hesse, Germany ; and Hohlen- 
stein, near Ulm, South Germany (Forsyth Major). 
In England the genus makes its first appearance, with 
Lemmus, in the brick-earth of Erith, Thames Valley (Newton, 
Geol. Mag., October 1890, 454), and is present also in later 
pleistocene deposits. It was extremely abundant, and occurred, 
as first pointed out by Forsyth Major (of. cz¢., 123), as two 
cotemporary species now both extinct, D. gulelmi and D. 
henselae. 
Of these, D. gulielmi* was described from specimens in the 
Taunton Museum, obtained in Wookey Hole Cave, Somerset. 
It is characterised by large size, short and broad incisive 
foramina, broad nasals, and heavy teeth, 7’ and m”* having minute 
postero-internal salient angles. Hinton has identified it from 
Langwith Cave, Derbyshire (Aux. and Mag. Nat. Hist., July 
1910, 38; Forest of Dean Cave, Gloucestershire; Crayford 
and Erith brick-earth; Kesh caves, Co. Sligo, Ireland (where 
Dicrostonyx was very numerous in some strata), and from 
France. 
The other species, Dzcrostonyx henseli of Hinton (af. czt., 
37), described from a skull in the collection of Abbott, from 
Ightham Fissures, Kent, has also been identified from the 
Arctic Bed of Angel Road, Tottenham, Middlesex (Hinton, 
Quart. Journ. Geol. Soc., June 1912, 249); Langwith Cave, 
Derbyshire; Doneraile Cave, Co. Cork (where Decrostonyx 
occurred with Zezzmus in enormous numbers, see Ussher, 
op. cit. supra, p. 394); as well as from Quedlinburg (Hensel’s 
original skull of amdézguus, the dental peculiarities of which 
were noticed by its discoverer). This is a small species 
with reduced tooth-pattern, m' and m’ lacking the minute 
postero-internal salient angles, and having the posterior wall 
of the postero-external triangle reduced; it thus resembles 
rather D. hudsonius of Labrador, but is smaller than that 
species ; it has also less expanded nasals, the presphenoid bone 
is reduced to a mere rod, and the teeth are heavier. 
Remains from the following localities have not been assigned 
1 Arvicola gulielmi, Sanford, Quart. Journ. Geol. Soc., xxv., 1870, 125, pl. viii., 
figs. 4 and qa. 
VOL. II. 2C2 
