HiNTON — The Fossil Hare of the Ossiferous Fissures of Ightham. 241 



than in the latter. Moreover in L. variabilis they are narrower transversely, 

 and form a slightly longer series (see Table III.). 



Anterior upper premolar (p. 3). 



Blasius' laid great stress upon the diagnostic value of the anterior 

 premolar (p. 3) in distinguishing L. variabilis from L. eiiropams ; but 

 Nathusius,- who helped Blasius to draw up the diagnoses of the two 

 species, with further material, came to the conclusion that the alleged 

 difEerences were inconstant — a conclusion which Woldrich^ accepted. More 

 recently Lonnberg^ has stated that " the foremost premolar is more 

 simple in L. europwus, witli, as a rule, only two enamel folds, while 

 the same tooth in L. timidus [i.e. variabilis^ has three." The difference 

 appears to me to lie in the fact that the antero-internal cusp and the internal 

 fold (" 8 " and " a " respectively of the figures) are more reduced in 

 L. europceus than they usually are in the L. variabilis group ; but in the 

 latter group, at all events, this tooth is subject to great variation, due no 

 doubt partly to age, individual diiferences, &o., but partly also to race. 



In what may be considered as the typical form of this tooth in L. vari- 

 abilis the antero-internal cusp " 8 " is strongly developed, and the inner fold 

 "a" is transverse and rather deep. Such teeth appear to be common in the 

 Scotch and Arctic forms. 



Besides the two skulls described above, I have before me three palatal 

 specimens, with the p. 3 in place from the Ightham fissure. In the skull 

 belonging to Messrs. Corner and Kennard, and in the three palatal specimens 

 the p. 3 is of the typical form ; in addition the right p. 3 of the skull (fig. 1a) 

 shows an interesting feature, the large antero-internal cusp " 8 " being here 

 cut by a little enamel fold " «." In six skulls, among the twenty-eight 

 Scotch examples in the British Museum, the anterior premolar shows a similar 

 complication. In three of these, viz., " Altyre, Morayshire, 94. 2. 15. 2 ? (ad) "; 

 " Cromlix Dunblane, 97. 10. 18. 1 3 (ad)"; and " Nairn, 99. 5. 1. 2 (young)," it 

 is seen in both the right and the left teeth, while in the remaining three it is 

 seen on one side only, viz., " Cromlix Dunblane, 97. 2. 15. 8 ? (ad)," right 

 p. 3 ; "Cromlix Dunblane, 97. 2. 15. 5. S (ad)," left p. 3; and " Altyre, 

 Morayshire, 93. 12. 4. 3 (J (ad)," left p. 3. In a young skull of L. scoiicus, 

 in the Eoyal College of Surgeons (No. 3283), the p. 3 on either side 



^ Blasius, " Saugethiere Deutschlands," 1857, pp. 416 and 420. 



* Nathusits, " Ueier die sogenannten Leporiden," p. 22. 



' WoLDKiCH, Sitz. d. h. Akad. d. Wein. math.-nat. CI., Ixxxii. Ed., ii. Abt., p. 14. 



* LoNNBEBG, Proc. Zool. iSoc. 1905, vol. 1., p. 282. 



SCIBNI. PEOC. E.D.S., TOI. XTl., HO. XSIU. 2 B 



