xxxviii INTRODUCTION. 



applied the specific name from their close resemblance to the Spermophilus erythrogenys, 

 Brandt,^ of Siberia. 



Species Spermophilus citiUus, Pall. — A third jaw in the same collection differing from 

 the preceding in its greater stoutness, and in the greater outward extension of the process 

 between the angle and condyle, is most closely allied to the pouched marmot, Spermophilus 

 citillus found near the snow-line on the high mountains of central and northern Europe. 



Remains of several individuals of this genus have been discovered by Dr. Blackmore 

 also in the low-level gravels of Fisherton, near Salisbury. Unfortunately, from the very 

 large number of the living species that must necessarily be examined before an accurate 

 determination can be made, we have been unable to determine these in time for the 

 Introduction, which we publish now in an imperfect state rather than keep back till the 

 end of the work. 



§ 10. If we now pass on to consider the relation which exists between the British 

 Pleistocene mammalia and those now living on the earth, we shall find that the former 

 fall into five distinct groups : the first comprehending all the extinct species ; the second, 

 those confined at the present day to northern chmates ; the third, those confined to 

 southern ; the fourth, those common to northern and tropical climates ; and lastly, those 

 still inhabiting the temperate zones of Europe. 



§ 10, A. Extinct species. — Out of the fifty-three species, omitting Bos longifrons, 

 which has not yet been proved to have inhabited Pleistocene Britain, but fourteen are no 

 longer to be found on the face of the earth : 



Machairodus latidens. 

 Ursus spelaeus. 

 Megaceros Hibernicus. 

 Cervus dicranios. 

 Elephas antiquus. 



„ primigenius. 



„ priacus, 



Elephas meridionalis. 

 Hippopotamus major. 

 Rhinoceros tichorinus. 



„ megarhinus. 



„ leptorhinus. 



„ Etruscus. 



Castor trogontheriura. 



And it is a fact well deserving of note that of these more than half had already begun to 

 live in the preceding period. Thus, the Pliocenes of the Val d'Arno, near Florence, are 

 characterised by the occurrence of Machairodus, Elephas antiquus, E. meridionalis, E. 

 priscus, Rhinoceros Etruscus, Hippopotamus major, diU^Cervus dicranios, while the Pliocene 

 strata of Montpellier have yielded the megarhine rhinoceros, which probably occurs also 

 in the former locality. The Castor trogontherium may perhaps turn out also to have 

 existed in PHocene times ; but at present we know nothing of the age of the sandy deposit 



1 'Deux nouvelles especes de Sonsliks de Russia' (Spermophilus Erersmanni et Erythrogeuys), Bull. 

 Scient. Acad., St. Petersb., t. ix (1842), p. 43. 



