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Show 462 MESSRS. BLACKMORE AND ALSTON [June 16, Mountains; and it is widely but locally distributed throughout Britain. Its fossil remains do not appear to have been recognized, except in France and England. The molars of this species are distinguished from those of all the other known Voles (except the nearly allied A. rutilus, Pall.) by the development in the adult animal of distinct roots, whence it has been generically separated under the name Hypudaus, Illig.* The enamel-folds are proportionally thicker than in the other species, the cemental spaces are more rounded, and the anterior ones of the first lower molar are more distinctly separated. The pattern, which is liable to slight individual variation, especially in the third upper molar, is as follows:- Tipper I. 5 spaces 6 angles. Lower I. 7 spaces 9 angles. II. 4 „ 5 „ „ IL 5 „ 6 „ „ III. 6 „ 7 or 8 „ „ III. 3 „ 6 „ W e have examined the specimens in the British, Taunton, and Norwich Museums, and in our own collection. 2. ARVICOLA AMPHIBIUS (Linn.). 1823. Water-Rat, Buckland, Rel. Diluv. p. 18, plate xi. figs. 1-6, 12-18. 1825. Campagnol des cavernes, Cuvier, Ossem. Foss. v. pt. i. p. 54. 1846. Arvicola amphibia, Owen, Br. Foss. M a m m . p. 201, fig. 76. 1846. (?) Arvicola, sp.?, Owen, ibid. p. 205. 1847. "Hypudaus spelaus, Cuv.," Giebel, Fauna der Vorwelt, i. p. 88. 1852. (?) Arvicola antiquus, sp. n., Pomel, Ann. Sc. de l'Auvergne, xxv. p. 361. 1852. (?) Arvicola robustus, sp. n., Pomel, ibid. p. 362. 1855. (?) Arvicola, sp.?, Lvell, Man. Elem. Geol. (5th ed.), pp. 156, 168, fig. 146. 1866. Arvicola amphibia, Boyd Dawkins & Sanford, Pleist. M a m m . (Introd.) p. xxxvi. 1869. Arvicola amphibius, Boyd Dawkins, Q. J. Geol. Soc. xxv. p. 194. 1870. Arvicola amphibius, Sanford, ibid. xxvi. p. 124. Dr. Buckland found the remains of the "Water-Rat" so abundant in the Kirkdale Cave that almost every fragment of the osseous breccia which he examined contained teeth or broken bones, several of which he figured. Cuvier examined specimens from the same locality, and found them to agree well with this species, but remarked that, although larger than the remains from Sardinia and Corsica ( = A. brecciensis, see p. 466), they were smaller than the recent A. amphibius. On this observation Dr. Giebel founded his "Hyp. spelaus, Cuv." Prof. Owen, however, found that speci- * Dr. Forsyth Major mentions a large species, resembling A. amphibius but with rooted molars, as found in the lignites of Leffe, in Lombardy, but has not yet named or described it (Atti Soc. Ital. Sc. Nat. xv. p. 584). |