HiNTON — The Fossil Hare of the Ossiferous Fissures of Ightham. 229 



The skull of L. var. gnenlandicus^ is at once distinguished by the form of 

 the rostrum and the curiously straiglitened upper incisors, which project far in 

 front of the nasals. The incisors of the Ightliam skulls, and those from 

 Zuzlawitz (Pleistocene), according to Woldricl),^ when compared witli the 

 Alpine, Scotch, and Irish forms of L. variabilis, are seen to be straighter ; 

 but this straiglitening is very much less than is seen in L. var. r/nenlandicus. 



L. var. ainu^ has the brain-case proportionally very narrow ; and the 

 extreme length, compared with the basal length, is very short. L. var. 

 tschuktschoram^ is characterized by its great zygomatic breadth. 



In his description of the Somerset skull, Sauford says'^ : — "The frontals 

 differ in form from tliose of every hare witli which we have compared them, 

 with the exception of the much smaller form, L. altaious, of the British 

 Museum Catalogue ; but in the skulls of this animal the post-orbital processes 

 are much less developed, and do not extend so far back as the parietals, with 

 whicli tliese processes coalesce in the fossil." In the smaller of the two skulls, 

 labelled L. " aUaicus" in the British Museum (Zool. Dept., No. 50. 5. 28. 3), 

 which is the one, I think, that Sauford had in mind, the constricted temporal 

 part of the frontals is short antero-posteriorly, so that the brain-case appears 

 rather abruptly truncated in front ; and the fossil skulls from Ightham are 

 similar in this respect. But one finds the same frontal form together witli the 

 very massive superciliary processes (which characterize not only the Somerset 

 but the Ightham skulls) frequently in the skulls of L. variabilis scoticus, and 

 occasionally in those of L. var. hibernicus. When viewed from the front, the 

 superciliary processes of the Ightham skulls rise more gently from the frontal 

 surface, and the median convexity of the frontal is less bold tlian in L. var. 

 scoticus, so that the superior transverse contour appears flatter in tlie fossil 

 skulls ; and in this respect they agree exactly with L. var. hibernicus (PI. XV., 

 fig. 3). 



As regards size, the skulls of L. var. scoticus are smaller than those of 

 L. var. hibernicus ; and these again are smaller than the fossil skulls. If the 



1 Lyon, " Smithsonian Miscellaneous Collections," vol. xlv., pis. 80 and 81, fig. 7. This is the 

 name by which Rhoada proposes to distinguish the Greenland Hares from those inhabiting the western 

 coast of Davis Straits. Winge, however, says that there is no specific distinction, and that Rhoads 

 has only seen the extreme form of the Greenland Hare (Gronlands Pattedyr, p. 373). Judging from 

 the material before me, both the highly specialized form which Ehoads calls Z. grmnlandiciis, and the 

 more normal form, for which he uses Jioss'sname of L. arcticus (= L. glacialis Leach), and which he 

 only knows from the regions west of Davis Straits, inhabit Greenland. I agree with Winge that 

 there is no specific distinction between them ; but as the two forms are very different iu skull, I think 

 it better, at all events for the present, to keep them apart as sub-species of L. variabilis. 



= "WoLDKiCH, Sitzb. d. k. Akad. Wien. math.-nat. CI., Ixxxii. Bd., ii. Abt., p. 15. Winge, 

 " Gronlands Pattedyr," pp. 358 and 376-378. 



' Barrett-Hamilton, Proc. Zool. Soc, 1900, p. 90. 



■• I/Yo.v, loc, cit., fig. 3. 



^ Sanford, Quart. Journ. Geol. Soc, vol. xxvi., p. 127. 



