45-2 



SPERMOPHILUS. 



IX. NOTE ON THE OCCUKKENCE OF 8PERM0- 

 PHILUS IN THE CAVE FAUNA OF ENGLAND. 1 



The glacial or northern character of the greater part of the Cave 

 Fauna of England is so well-known, that no surprise will be excited by 

 the announcement of the addition to it of a mammal genus, the habitat 

 of which is now restricted to the Arctic Circle and the northern parts 

 of Europe, Siberia, and America. 



In 1842, MM. Desnoyers and Constant Prevost announced the dis- 

 covery of abundant remains of Spermophilus (citillus), from the bone- 

 breccia of the caves and fissures of Montmorency, in the gypsum of the 

 Paris Basin. 



In 1859, while examining the rich collection of fossil bones, made 

 by the late Rev. Daniel Williams, from the numerous caves of the 

 Mendip hills, and now preserved in the Museum of the Somersetshire 

 Literary and Philosophical Society at Taunton, I detected two rami 

 of the lower jaw of a species of Spermophilus, which, by the kindness of 

 the Rev. W. Arthur Jones, I was enabled to compare with recent 

 specimens in the metropolitan collections. 



The most perfect remain consists of a right ramus, containing the 

 incisor and three last molars in situ. The most anterior of the molar 

 series (last premolar) is wanting, probably a recent loss, as the alveolus 

 is free from matrix. The jaw is in a singularly good state of preserva- 

 tion, showing the condyle, coronoid, and posterior angle, quite entire ; 

 the only damage being a slight abrasion of the lower margin near the 

 angle, and a small film broken off from the anterior side of the incisive 

 sheath. Figs. 1-3 of Plate XXXV. represent the fossil, top and side 

 aspects : fig. 1 showing the crowns of the molars, and figs. 2 and 3 

 respectively the inner and outer sides of the jaw erect. 



The well-known characters of the genus Spermophilus are so clearly 

 shown by the fossil, that it is not necessary to describe the teeth in 

 detail. The following are the principal dimensions of the Spermophilus 

 from Taunton : 2 



April 8, 1858. — Length of jaw from posterior surface of condyle to anterior edge 

 of incisive sheath, T35 in. Ditto from posterior angle (lower margin) to ditto, 

 1-35 in. Length of three posterior molars, 0'4 in. Length of line occupied hy 

 the four molars, 0'52 in. Length of diasteme, - 32 in. Length of mentary suture, 

 032 in. Length of exserted portion of incisor, 0'25 in. Length from posterior 

 margin of condyle to anterior edge of coronoid, 0'33 in. Length from bottom of 

 sinus between condj'le and posterior angle to anterior edge of masseteric disc, 0'7 

 in. Length from ditto to anterior edge of incisive sheath, 1-2 in. Height of coro- 

 noid to line of bottom of sigmoid notch, 0-22 in. Width of ditto at the middle, 

 - l in. Extreme height of jaw to the apex of the coronoid, 0'65 in. Ditto behind 



1 This paper was commenced in 1858, 

 but was never completed. The defici- 

 ency has been supplied by extracts from 

 the author's Note-books, and from a 



letter to M. Lartet.— [Ed.] 



2 The remainder of the paper is made 

 up of extracts from the author's Note- 

 books, &c— [Ed.] 



