FOSSIL AND EECEjN'T LAGOMOKPHA. 467 



part, turning backward, rims ajiproximately parallel with the anterior border of the 

 tooth, and is slightly folded from behind, so that it may be compared with an 

 outspread fork. Figs. XVI and XVII, re2:)resenting the left incisors of two 

 specimens from Mexico in the Nat. Hist. Museum, labelled Lepus callotis, show this 

 same form, with a slight complication of the transverse part in one of them (XVII). 

 L. melanotis, Mearns (fig. XV), from Clapham, New Mexico, belonging to the same 

 group {llacrotolagus), exhibits in the right incisor the T pattern in a much reduced 

 form, and in the left a condition approximating to that of the African L. saxatilis, of 

 which more hereafter. 



The nearest apjjroach to L. callotis is seen, according to Hilgendorf, in L. dayaims, 

 Blf., to which species he refers also the L. nlgricolUs of the first note. I have figm-ed 

 (fig. XVIIi) the right incisor of the co-type of L. dayanus, from Sukkur, Sind (Br. Mus. 

 Z. D. No. 90.4.9.2), which corresponds almost exactly to Hilgendorf's description. A 

 nearly similar form I find to lie exhibited by L. hainanus, from Hainan (fig. XIX) ; the 

 folding, however, is considerably shorter, and the opening broader. In L. nigncollis 

 from Ceylon (fig. XXI) the branches of the fork are more elongate, and the anterior 

 opening is considerably more constricted, than in L. hainainis. 



L. feguensis, Blyth, from Pegu (fig. XX), shows a further complication, already 

 foreshadowed by one of the callotis specimens (fig. XVII), there being three branches 

 of the fork. Not much different is the left incisor — the rio-ht one is damaijed — of a 

 L. nigricoUis from the Nilghiris (fig. XXII), and both incisors of L. ruficaudatus 

 [L. kurgosa, Gray) from the Punjalj (fig. XXIII). The maximum of complication 

 known to me is exhibited by a L. ruficaudatus from Rajputana (fig. XXIV), where the 

 left incisor exhibits a four-branched fork, the right being a slight modification of the 

 same pattern. 



Following the description of the incisors of L. dayanus, Hilgendorf gives that of an 

 vindetermined skull brouglit home from Africa by the Von der Deckeu Expedition. In 

 this the T with a narrow opening is still strongly marked, but the median moiety of the 

 transverse part is reduced. The whole of the enamel-fold occupies less sjoace than 

 in L. dayanus, not being so much extended either backward or laterally *. This 

 description applies fairly well to my fig. XIV, L. Victorice, Thos., from Nassa, Victoria 

 Nyanza, except that the opening of the fold is not narrowed. 



Pigs. IX, X, and XII represent L. saxatilis, F. Cuv., from Pirie Bush, Kiag William's 

 Town (Cape), Transvaal, and " Cape of Good Hope " respectively, in none of which 

 IS there a bifurcation at the posterior end ; the folding penetrates far backward and 

 the opening is wide, as described by Hilgendorf f in L. saxatilis. Fig. XI, '^ Le^ius 

 sp.", from Sena, Zambesi, is of the same pattern ; and so is L. Whytei, Thos., type- 

 specimen, from Pacombi P^iver, Nyasa (fig. XIII) ; in the latter, however, the fold 

 penetrates further back than in figs. IX-XII, and the opening is comparatively more 

 restricted. To this form seems to approach Hilgendorf's specimen of " Lepus cajjcnsis," 



* Op. cit. p. 20. t 0/>. (■('. p. '21. 



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