FOSSIL AND RECENT LAGOMOIIPIIA. 469 



from Mozambique *, collected by Peters, which, however, is certainly not a Lepm capensis. 

 The latter differs scarcely from i. enropceifs, Pall., s. 1. (including L. oecidentalis, de 

 Wint.), by its minute enamel-folding-, not filled with cement. 



The forms which remain to be described (figs. I-VII) are all approximately of the 

 same type, viz. a triangular fold with the apex turned backward ; the fold in none 

 of them stretching so far back as in Caprolagm hispidus (fig. VIII), mentioned above. 

 The pattern of the latter is approached somewhat by that of fig! VII, from 

 a specimen labelled '' Lepus ^arkaiidensis?," from Koko Nor (Br. Mus. Z. D. 

 No. 94.2.2.12), exhibiting an enamel-fold with thick borders, but shorter than in 

 C. hispidus, and with a much wider opening. It is decidedly not L. ijarkaiidensis, Giinth. 

 The type of the latter, which is not figured, approaches in the form of the folding 

 L. sinensis, Gray, the type of which (Br. Mus. Z. D. No. 38.10. •-'9.23) is represented in 

 fig. V. Both are imperfectly filled with cement, in L. sinensis still less so than in 

 L. tjarkandensis. The latter differs also from the former by the opening and the 

 whole fold being narrower. 



L. tihetunHs, Waterh., has no trace of cement ; in the shape of its fold it is 

 intermediate between the former two ; the opening is slightly broader than in L. yark- 

 andensis. 



The conformation of the type of Gray's '-i. Judicce " (fig. IV), from Palestine, and 

 of "i. sinuificus" (fig. Ill), from Midian, N.W. Arabia, almost identical in both, is 

 shown by the figures. 



L. timidus, Linn. {L. i-ariahiUs, Pall.) (figs. I & II) hardly differs, Imt still the two 

 figures of this species show that there are slight differences between a specimen 

 from Prussia (fig. I) and one from Scotland (fig. II). In this species I have always 

 found the enamel-fold with a filling of cement, though very often incomplete. In 

 L. europceus, Pall., I have never met witli a trace of cement. This difference would 

 seem to be a good character for distinguishing isolated fossil incisors of the two species ; 

 but it is probable that much-weathered specimens of L. timidus may have lost their 

 cement. 



Lepus cumanicus, Thos., from Venezuela (Br. Mus. Z. D. No. 94.9.25.18), the type of 

 which is represented in fig. VI, stands somewhat apart l)y its very narrow and 

 comparatively elongate enamel fold. 



Hilgendorf holds these complications of the enamel in the upjier incisors to be a 

 specialization, the only reason given being that in the fossil Prolagus {3L/ol((gus) nothino- 

 of the kind is seen. " Phylogenetisch betrachtet, ist die bedeutende Schmolzentwickluno- 

 des Lepus mexioanus gleichfalls ein Extrcni ; denn die Einbiegung der Schmelzplatte an 

 der Vorderflache tritt bei den fossileu Leporidea-Gattungen {Myolagus) als eint; seichte 

 Einknickung auf , deren Seitentheile fast die ganze Vorderflache einnehmen " t. This 

 argimient would be of some weight if Prolagus could be considered ancestral to 

 Lepus ; but this is certainly not the case, although the molars of the former are of a 

 more primitive type than those of the latter. As insisted upon in the jiresent 

 memoir, the Lagomyida?, of which Frolagns is a member, run parallel with the 



* Oj:i. fit. p. 21. t Ojj. cit. p. 20. 



