1874.] ON FOSSIL ARVICOLID.E. 467 



1847. Hypudceus brecciensis, sp. n., Giebel, Fauna d. Vorwelt, i. 

 p. 88. 



1855. Arvicola ambiguus, sp. n., Hensel, Zeits. d. Deutsch. Geol. 

 Ges. vii. p. 469, pi. xxv. figs. 3, 8, 9 {nee Porael). 



1859. Arvicola brecciensis, Gervais, Zool. et Paleont. Franc. (2 me 

 ed.)p. 41. 



A species of Arvicola, found in the breccia of the Mediterranean 

 islands, was described but not systematically named by Cuvier, and 

 subsequently by Wagner (Karsten's Archiv, xv. p. 10) ; and on 

 these descriptions Dr. Giebel founded his Hypudceus brecciensis. 

 On the ground that Giebel had not given sufficient diagnostic cha- 

 racters, Hensel re-named it A. ambiguus, overlooking the previous 

 employment of that name by Pomel (see below, p. 469). Hensel 

 defines the species as having three external and three internal angles 

 to the third upper molar, and/owr external and five internal angles 

 to the first lower molar. He considers that its nearest affinities 

 among living forms were with the Siberian A. obscurus, the size and 

 the form of the first lower molar agreeing well with Middendorff's 

 figure of that species ; but the third upper molar was very different, 

 and the facial portion of the skull was shorter. 



According to Hensel's figures and description, the pattern was : — 

 Upper I. 5 spaces, 6 angles. Lower I. 7 spaces, 9 angles. 

 II. 4 „ 5 „ „ II. 5 „ 6 „ 



» HI- 5 „ 6 „ „ III. 4 „ 6 „ 



We have not seen specimens of this Vole ; but if Hensel's charac- 

 ters are constant, the species would appear to be a good one. 



6. Arvicola agrestis (Linn.). 



1823. Young Water-Rat, Buckland, Rel. Diluv. p. 265, plate xi 

 fig. 11. 



1825. Petit Campagnol des Cavernes, Cuvier, Ossem. Foss. v. 

 pt. i. p. 54. 



1846. Arvicola agrestis, Owen, Br. Foss. Mamm. p. 206, fig. 77. 



1847. Hypudceus bucklandii, sp. n., Giebel, Fauna d. Vorwelt, i. 

 p. 88. 



1852. (?) Arvicola arvaloides, sp. n., Pomel, Ann. Sc. de l'Au- 

 vergne, xxv. p. 362. 



1852. (?) Arvicola joberti, sp. n., Pomel, ibid. p. 363. 



1866. Arvicola agrestis, Boyd Dawkins & Sanford, Pleist. Mamm. 

 (Introd.) p. xxxvi. 



1869. Arvicola agrestis, Boyd Dawkins, Q. J. Geol. Soc. xxv. 

 p. 194. 



1870. Arvicola agrestis, Sanford, ibid. xxvi. p. 124. 



Small remains of Arvicolce, found in the Kirkdale Cave, were 

 attributed by Dr. Buckland to "young Water-Rats." He sent spe- 

 cimens to Cuvier, who observes that they were not larger than A. 

 arvalis, but that a femur was proportionally thicker, and that the 

 pelvis figured by Buckland resembled A. oeconomus rather than A. 

 arvalis. At that time A. agrestis was universally confused with the 



