HiNTON- — The Fossil Hare of the Ossiferous Fissures of Ightham. 227 



examined by me, in only one instance, viz., a skull of L. var. hibernicm 

 (B. M. 3. 1. 28. 1), is an approach towards the constriction of the temporal 

 region of L. europceus seen. 



A still more important character is that afforded by the anterior part of 

 the zygoma. The malar is frequently deeper in L. variabilis than in L. 

 europceus ; and the groove on its outer surface lodging the deep part of tlie 

 masseter lateralis extends further forwards in the former species than it does 

 in tlie latter. If one measures the least distance between the anterior edge 

 of this groove and the front vertical border of the zygoma, one finds that it 

 is considerably less than the vertical height of the zygoma measured in the 

 same region in L. variabilis, whereas the converse condition is found in L. 

 europceus.^ Hilzheimer" lias stated this to be inconstant ; but he has, in my 

 opinion, confused skulls of L. variabilis with those of L. europceus ; at any 

 rate, in tlie material before me the distinction is quite clear. 



Winge'' and Lonnberg^ have given some further characters relating 

 to tlie length, breadth, aud form of the nasals in the two species, and tliese 

 appear to me to be borne out by the material. Another important cliaracter, 

 first pointed out by Woldrich,* and more recently by Winge," is that, while 

 in L. europceus the anterior upper incisor is quite confined to the premaxillary, 

 in L. variabilis this tooth extends its alveolus backwards, so as to impinge 

 upon or just enter the maxillary bone ; and its termination is marked by a 

 palatal swelling whicli is absent in L. europceus. 



After the Tables I. aud II. had been drawn up, I received from 

 Dr. Hilzheimer a copy of his recent paper. The " Basilarlauge " of his 

 table of measurements' is a different measurement from the " basal length " 

 as liere given. In my tables the measurement expresses the distance between 

 the anterior margin of the foramen magnum and the most anterior point of 

 the premaxillary. Certain of Hilzheimer's measurements do correspond with 

 mine ; and in order to compare them, the measurements in question were 

 reduced to values of the "extreme length" taken as 100. The results of 

 this comparison are summarized in Table III. ; aud attention is here called 

 to this summary, as it serves to bring out certain differences of proportion 

 which characterize the skulls of the two species with great clearness. It 

 would appear from the table that the zygomatic breadth and least frontal 



' LoNNEEHG, op. cit., p. 280. 



- Hilzheimer, op. cit,, p. 406. 



3 WiNGE, " Gronlands Pattedyr," p. 358 ; " Pattedyr," pp. 58, 61. 



* LoNNBERG, op. cit., p. 280. 



» WoLDRiCH, Sitzb. d. k. akad. Wien. math.-nat. 01. , Isxxiv., Bd. 1, Abt., p. 220. 

 ^ WiNGE, " Gronlands Pattedyr," p. 358 ; " Pattedyr," pp. 58, 61. 

 " Hilzheimer, op. cit., pp. 416, 417. 



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