450 DR. C. I. FOESTTH MAJOR ON 



Lagonii/s, on account of its having one superioi' molar less than the genus Lepus; adding, 

 however, that the Sansan fossil has one inferior molar less than the existing Lagomi/s. 



For this same Rodent from Sansan, Pomel proposed to create the sub-genus Prolagiis, 

 on the ground of its differing from Lagomys " par la derniere molaire inferieure, qui a 

 trois pi"ismes par reunion de la cinquieme molaire a la quatrieme. Du reste, la premiere 

 est aussi triangulaire. On pourrait nommer I'espece Prolagus sansaniensis." The 

 hypothetical fusion of two molars, stated here as an undoubted fact, does not stand 

 close investigation, any more than in the case of Tiiaiiomi/s. But to this I shall return 

 in the sequel. 



An excellent description of the remains of the lagomorphine Rodent from the 

 ossiferous breccia of Sardinia is eiven bv Hensel. He foimds on them his new trenus 

 Ilyolugus, and poiats out that one of the two Lagomyidae from ffiningen, Lagomys 

 Meyeri, v. Tschudi, is closely related to the Sardinian fossil, and therefore likewise to 

 be placed in the genus Mi/olagm. (It is a pity that the perfectly well-characterized 

 Mi/olagus has, for priority's sake, to give way to Pomel's " Prolagus," just as it is to be 

 regretted that Pomel's amply-described Lagodus has to stand back before H. v. Meyer's 

 imperfectly characterized Tltanomj/s.) Hensel refers to Pomel's Prolagus *, and rightly 

 observes that the characters mentioned by the latter writer recall to mind the genus 

 Myolagus ; he considers them, however, to be insufficient for a decision. This was quite 

 true at the lime when Hensel wrote. It is incorrect to say, as has been done by 

 H. V. Meyer f, that Hensel based his genus uniquely on the form and number of the 

 lower cheek-teeth and the position of a foramen mentale. Hensel had laid great stress 

 also on the pattern of the upper teeth %, a character which H. v. Meyer, as in the case 

 of Titanomys, studiously avoids discussing. 



A step backward is made by Fraas, when he figures and describes a well-preserved 

 mandibular i-amus from Steinheim under the name of Arclueornys steinheimensis. He 

 was set right by H. v. Meyer §, who referred the supposed Archceonnjs from Steinheim 

 to '■'■Lagomys {Myolagus) Meyeri, Tschudi," and in 1870 he atoned for his mistake by 

 giving a full description of the Steinheim Eodent in question. 



Prolagus ceningensis. 



Anoeiiia wiiinyciisis, Kuuig, Icoues Poss. Sect. pi. x. fig. 126 (1825). 



Lai/omys ceninycnsis, p. p. H. v. Meyer, Neu. .Jalirb. p. 58 (1836). 



Lagom;/s wninyensis, Waterliouse, Nat. Hist. Mamnialia, ii. p. 32 (18-18). 



Lagomys Meyeri, v. Tschudi, iu H. v. Meyer, Zur Fauna d. Vorwelt. Foss. Saugeth. etc. von ffiningeii, 



p. 6, pi. ii. figs. 2, 3, pi. iii. fig. 2 (1815) ; Lydekker, Cat. Foss. Mamin. Brit. Mus. i. p. 257 



(1885). 

 Layovujs xa/)saniensh\ Lartet, Not. Coll. de Sansan, p. 21 (1851). 

 Frolayiis nunsainensis, Pomcl, Cat. metli. p. 43 (1853). 



* Oil. cit. p. 702. 1 I'alaiioutogT. xvii. p. 228 (IS70). 



+ Oj,. cit. p. sy.5. § Neu. J;ihrb. 1864, p. lt»7 ; 18(35, p. S43. 



