230 IScientlfic Proceedings, Royal Dublin Society. 



proportional measurements (Table II.) be compared, it will be seen that tlie 

 Igbtham skulls most closely correspond with those of the Irish Hare. The 

 skulls here referred to, L. var. arcticus, Ross (= L. glacialis. Leach) , principally 

 differ in their somewhat greater zygomatic breadth. L. var. varronis^ also 

 comes near to the fossils as regards the temporal part of tlie frontals and the 

 form of the brain-case ; but it is distinguished by its much smaller size and 

 by the much gentler way in which the sides of the post-palatine vacuity fall 

 away from the inner alveolar border. 



As what I have to say about Hilzheimer's^ classification of the European 

 Hares depends principally upon the skulls, it will be convenient to deal witli 

 it here before passing on to the consideration of the lower jaw. Hilzheimer 

 distinguishes three species of Hare as inhabiting the European mainland and 

 Britain, viz., L. variabilis, Pall (= timidtis, Linn.), L. curopmus, Pall, and 

 L. medius, Nilsson. 



Blasius long ago gave a good account of L. medius, Nilss.,^ and of 

 L. aquilonius, Bias., and L. crispicus, Ehrenberg (the two latter forms being 

 regarded by Hilzheimer as subspecies of L. medius, Nilss.) ; and he showed 

 conclusively tliat these three forms were nearly allied to each other, that 

 cranially they were, according to the then prevalent idea of the nature of 

 species, indistinguishable from L. europceus, and that in fact they were merely 

 climatic pelage pliases characteristic of tlie northern and eastern parts of the 

 range of L. europceus. That Blasius' opinion as to the cranial identity of 

 " L. medius " with L. europceus is correct is proved by a reference to the 

 analysis of Hilzheimer's measurements of the skulls from Sarepta,* which 

 he regards as probably referable to L. caspicus, Ehrenberg, given in Table III. 

 of the present paper. Except that the molar series is a trifle shorter, there 

 is nothing to distinguish L. " medius " caspicus from L. europceus typicus. 

 Further, it may be mentioned here tliat the two skulls from Sarepta 

 mentioned by Hilzheimer'* as possibly referable to " L. timidus " [= variabilis'] 

 {"'i hyemalis"), are unquestionably to my mind referable to a form of 

 L. europceus, and probably are identical with L. e. caspicus, the proportional 

 values for these specimens being, in the order of Table III. :— 100 (100), 

 48-1 (45-5), 33-4 (32-3), 13-25 (14-15), 31-4 (31-4), and 17-2 (17-2). 



Hilzheimer does not stop, however, at recognizing L. ^^ medius" and its 

 two allies as forming a distinct species. He extends L. " medius " to include 



' Lyon, loc. ci(., fig. 8, 



- Hilzheimer, Jahreshefte des Vereins Jiir vaterl. Nattirk. in Wiirtt., 1908, p. 384. 



^ Blasius, " Sawgethiere Deutschlands," 1857, p. 414. 



^ HlLZHEIMEK, op. cit., p. 416. 



' HlLZHEIMEK, op, cit., pp. 409-417. 



