1874.] on fossil arvicolidjE. 463 



mens from Kent's Hole, agreeing closely in character with those 

 from Kirkdale, were not inferior in size to the existing "Water-Vole. 

 Dr. Schmerling figures what appears to be the present species from the 

 Belgian bone-caves ('Oss. Foss. des Cavernes de Liege,' 1833). In 

 1852 M. Pomel described two new species, A. antiquus and A. 

 robustus, from the Breche de Coudes and other French deposits, de- 

 fining them by slight cranial differences, probably attributable to 

 age, and by the anterior space of the first lower molar being rounded 

 in the first and almost triangular in the second — a variation con- 

 stantly met with in A. amphibius. 



In considering the size of fossil Voles allied to the present, it 

 must be remembered that several races now exist in Europe which 

 vary very greatly in this respect, and which are often regarded as 

 distinct species. Of these the best marked are A. amphibius (Linn.), 

 A. terrestris (Linn.), and A. destructor, Savi ; and it has been 

 shown by Blasius (Siiugeth. Deutschl. pp. 344-358) and by Fatio 

 (* Campagnols du Leman,' pp. 36-48), that although typical ex- 

 amples of each form are very different in size, proportions, and 

 external characters, yet they run into one another by such numerous 

 gradations that it is impossible to find constant characters by which 

 they may be defined and separated. Such being the case with the 

 recent animal, it is, of course, all the more impossible to separate 

 fossils by the teeth and jaws alone. 



Prof. Owen mentions some portions of upper and lower jaws from 

 " the older Pliocene crag near Norwich," found along with molars 

 of Mastodon angustidens, as indicating a species of Arvicola inter- 

 mediate in size between A. amphibius and A. agrestis. Sir 0. Lyell, 

 in his 'Elements' (5th ed.), figures these teeth, though on too 

 small a scale for satisfactory identification, but remarks that he does 

 not now regard these beds as older Pliocene, believing that some of 

 their fossils, including perhaps the Mastodon, may have been washed 

 out of the Red Crag. Prof. Owen having kindly informed us that 

 the specimens in question had been in the collection of the late 

 Miss Gurney of Northrepps, and were now in the Norfolk and 

 Norwich Museum, we applied, through our friend Mr. Southwell, 

 to the authorities of that institution, who most liberally allowed us 

 every facility for their examination ; and Mr. Reeve, the curator, 

 has also obliged us with the loan of specimens from his private 

 cabinet. Those from the Gurney collection are labelled " Ostend ;" 

 and Mr. F. W. Harmer kindly informs us that they are doubtless 

 from the preglacial forest-bed series at that place (between Buckton 

 and Hasbro', on the Norfolk coast). Mr. Reeve's examples are a 

 single jaw from the upper bed of crag at Bramerton, and others 

 from the freshwater beds overlying the forest-bed at Runton, near 

 Cromer: Mr. Harmer considers these last of similar age to the 

 Ostend deposits, and the fossils are identical in appearance. The 

 Bramerton jaw (fig. 1, a, p. 464) is not inferior in size to ordinary 

 English examples of A. amphibius, with which it perfectly agrees in 

 dentition. The same remark applies to some teeth from Ostend ; 

 but other specimens from that locality (fig. \,b, p. 464) and from 



