204 CASTORIDuE. 



birds ; and in masticating the bodies of these small animals 

 with their coarse conical teeth, many bones and fragments 

 of bone would be pressed outwards through their lips, and 

 fall neglected to the ground.' 1 



Whatever cause may have operated on the introduction 

 of the numerous Water-rats into the Kirkdale Cavern, a 

 similar effect has been produced in many other caverns, 

 both in this and other countries. Dr. Schmerling has 

 figured characteristic remains of both large and small 

 species of Arvicola from the caverns of Liege. The speci- 

 mens of upper and lower jaw of the Arvicola amphibia, 

 figured at the head of the present section, are amongst 

 several specimens of this species from the cave of Kent's 

 Hole, some of which are now in the British Museum. 

 Remains of the Arvicola amphibia, (lower jaws) were 

 found in the ossiferous cavern at Berry Head, Devon. 

 Some of the bones from the cavernous fissures at Oreston, 

 show marks of nibbling, which may be referred more pro- 

 bably to the incisors of a small Rodent, than to the canines 

 of a weasel.* 



Cuvier, to whom both specimens and drawings of the 

 Arvicola from Kirkdale were transmitted, acknowledges 

 that the jaws and teeth agree in size and other characters 

 with the common Water-rat, but he found the other bones 

 to be a little smaller, which led him to suspect that the 

 species was not the same ; but he adds that an entire 

 skull of the fossil Arvicola could alone determine the ques- 

 tion. So desirable a specimen has not, hitherto, been ob- 

 tained from any British cavern. An os innominatum, the 

 characteristic anchylosed tibia and fibula, and some verte- 

 brae of the Arvicola from Kent's Hole, are not inferior in 

 size to those of the existing Water-vole, with the dental 



* See ante, p. 118. 



