246 Scientific Proceedings^ Royal Dublin Society. 



Humerus. 



Besides the humeri of the skeleton from the Ightham Fissure, eight 

 other perfect fossil examples lie before me from the same locality, including 

 the one figured by Newton.' According to Newton^: — "The head of the 

 humerus of L. europcetis, when viewed from above, is found to be rounder 

 than in L. variabilis, being in the latter more elongated from before back- 

 ward, and tending to become parallel-sided." The measurements of the 

 recent humeri confirm this observation, the transverse diameter of the head 

 beiug greater in L. eurojiceus and less in L. variabilis than the antero-posterior 

 dimension. 



In this the Ightham fossils, including the humerus figured by Newton 

 and referred by him in his first paper to L. eiiropwus, agree with L. variabilis ; 

 but they distinguish themselves from the humeri of all the living forms of 

 this group of which I have seen the limb-skeleton by their really gigantic 

 size. Woldrich^ mentions two forms as occurring in the Fissures at Zuzlawitz, 

 viz., a small form but little larger than the alpine L. variabilis, and a larger 

 hare which agrees better with the arctic variety. But as Woldrich's measure- 

 ments show, the latter form from Zuzlawitz is far inferior in size to the fossil 

 animal of the Ightham Fissures. The Immeri described by Hescheler from 

 the Kesslerloch, Thaiingen,^ agree exactly in size with those of the smaller 

 form from the Zuzlawitz Fissures. 



1 Newton, Quart. Jottrn. OeoJ. Soc, vol. 1., pi. xi., figs. 5, S«. 

 ''Ibid., vol. Iv. , p. 421. 



' WoLDRiOH, SiUb. d. k. Akttd. d. Wien. math. nat. CL, Ixxxii. Bd., ii. Abt., p. 18, and ihid. 

 Ixxxiv. Bd., i. Abt., p. 224. 



' Hescheler, Neue Denlcschrift. d. allyemeinen Selnoeh. Ges.f. d. Ges.Nattirw., Bd. xliii., p. 86. 



