470 on fossil arvicolid,e. [June 16, 



from the Breche de Coudes, with twelve angles to the first lower 

 molar. Counting the anterior extremity as an angle, this agrees 

 with the present animal ; and the rest of his description applies so 

 well as to leave no doubt that he had a Lemming of this species 

 before him. Three years later Hensel recognized this species 

 among fossils from the diluvium of Quedlinburg, in Saxony, in the 

 Mineralogical Museum of Berlin. In this country we discovered it 

 in some numbers in 1865 in the drift- deposits at Fishertou ; and 

 next year Mr. W. Flower sent us some specimens for identification, 

 procured from "Wookey Hole. In 1870 Mr. Sanford recognized part 

 of a skull in the Taunton Museum as only differing from recent 

 specimens in being slightly larger. At the same time he referred 

 six lower jaws in the same collection to a new species of Arvicola, 

 which he provisionally named A. gulielmi, remarking that they 

 might prove the same as Pomel's A. ambiguus. Dr. Forsyth Major 

 has since pointed out that these appear to be the lower jaws of the 

 present species — a conclusion at which we had independently arrived, 

 and in which we believe Mr. Sanford now fully concurs. Remains 

 from Hohlenstein, near Ulm, are described by Dr. Forsyth Major ; 

 and a fine skull from Eppelsheim, near Darmstadt, is in the British 

 Museum. 



Middendorff has clearly shown (' Sibir. Reise,' ii. th. 2, pp. 87- 

 99) that M. hudsonius, Pall., M. groenlandicus (Trail), and Lemmus 

 ungulatus, Baer, are all identical with M. torquatus, whose range 

 may therefore be described as circumpolar. It is found in the 

 Hudson-Bay countries, in Novaja Zemlja, from the White Sea to 

 the Obi, in Taimyrland, on Baer Island, and Novaja Siberia, and 

 from the Lena to the Jana. It appears to be verv rare in Green- 

 land (c/. Brown, P. Z. S. 1868, p. 349), and *is not found in 

 Russian Lapland. Parry found a skeleton in N. lat. 82°, while it 

 reaches its most southern point in Unalaska, under N. lat. 54°. In 

 postpliocene times it appears to have extended at least as far south 

 as Germany, England, and the basin of the Loire. 



In this species the prisms of the posterior molars are not com- 

 pressed and twisted as in the typical Myodes, but are placed regularly 

 as in Arvicola ; and Hensel has consequently separated it as a new 

 genus, under the name Misothermus. The pattern, which appears 

 to be very constant, is : — 



Upper I. 7 spaces, 8 angles. Lower I. 9 spaces, 11 angles. 

 „ 11. o ,, 7 j, j, !!• o ,j 7 >» 



„ III. 6 „ 8 „ „ III. 4 „ 6 „ 



We have compared recent and fossil skulls in the British and 

 Taunton Museums and in our own collection. 



9. Myodes lemmus (Linn.). 



1855. Myodes lemmus, Hensel, Zeits. d. Deutsch. Geol. Ges. vii. 

 p. 486, pi. xxv. figs. 10, 11, 15. 



1870. Lemmus norvegicus, var., Sanford) Q. J. Geol. Soc. xxvi. 

 p. 125, pi. viii. figs. 3 a, b. 



