HiNTON — The Fossil Hare of the Ossiferous Fissures of Ightham. 257 



Winge takes the eondylo-basal length of the skull as his standard, while 

 I took the basal length. The average relation between the basal length and 

 condylo-basal length in the Hares appears to be as 100 : 110 ; and in section 4 

 of the table my results are reduced in this proportion so as to be comparable 

 with those obtained by Winge. Although not quite accurate, the figures 

 in section 4 relating to my material are accurate enough for the present 

 purpose. 



The first fact brought out by the table is that in the southern forms of 

 L. variabilis the limbs, in proportion to the skull length, are considerably 

 longer than in L. europceus. But in L. v. Mbernicus and the Ightham fossil 

 Hare the limbs are shorter relatively than in the Scotch form (represented 

 by the skeletons Nos. 3282 and 3283 Eoy. Coll. Surg.). The Norwegian 

 form measured by Winge apparently agrees with L. v. scoticus in this respect, 

 while, on the other hand, tlie Swedish L. variabilis of Winge's table agrees in 

 this with L. v. Mbernicus. The high northern forms have shorter limbs; and 

 the hind limb especially shows a tendency to return to the short-limbed 

 condition of L. europceus. This shortening is here probably a secondary 

 specializatioi induced by the frigid habitat, and not a primitive condition 

 as in L. europceus. 



The second point worthy of notice concerns the relation of the radius to 

 the liumerus. The southern forms of L. variabilis, including the fossil Hare 

 (in which it is marked), have the radius approximately equal to or a little 

 longer than the humerus, i.e. they retain the primitive relationship of these 

 bones found in the Eabbit. In L. europceus the radius becomes considerably 

 longer than the humerus ; and this specialization appears also in some of the 

 boreal forms of L. variabilis. I suspect that eventually it will be found to 

 be the normal condition of L. v. grceiilandicus. 



[Table. 



SCIENT. PROC. R.D.S., VOL. XII., NO. XXIII. 2t 



