368 Br. C. I. Forsyth Major — Some Rodents from Oeningen. 



I completely disagree : " Anf das Fehlen des letzten einfachen 

 Backzahnes bei den drei von fl. v. Meyer gezeichneten Exemplaren 

 darf wohl nicht allzuviel Gewiclit gelegt werden. Es ist nicht 

 unmoglich, dass ancli hier, wie bei Titanomys visenoviensis, im 

 normalen Kiefer nur drei zvveilobige Molaren vorhanden sind und 

 dass dalier der stif'tfcirmige m, 4 [meaning m. 3] des Hensel'schen 

 Originales als Analogon des bei T. visenoviensis abnorm vorkom- 

 menden Lobus des m. 3 [meaning m. 2J betrachtet werden muss." ' 

 This whole statement is somewhat vague and obscure ; the writer 

 seems to assume (1) that in T. visenoviensis both the m. 3 and a third 

 posterior lobe of m. 2 occur only abnormally ; and (2) that in 

 ' Lagomys verus ' the presence of a ra. 3 is likewise an abnormal 

 occurrence. From these two assumptions the inference is drawn 

 that in the type of Lagomys verus m. 3 is the ' analogue ' of the 

 equally 'abnormal' third lobe in m. 2 of Titanomys visenoviensis. 

 The writer concludes by saying that he is almost inclined to consider 

 the presence of m. 3 as a juvenile character, and that this tooth is 

 caducous (' hinfallig'). This is very pi'obably true with regard to 

 Titanomys visenoviensis, and I have myself suggested it in the memoir 

 in course of publication. The last lower molar of ' Lagomys verus ' is 

 caducous after a manner, viz., it has often dropped out in the fossil, 

 its alveolus being filled with matrix. But, as I shall show hereafter, 

 it is decidedly erroneous to consider this toolh as caducous in the 

 sense attached by Schlosser to this term ; and so are all the other 

 suggestions tentatively put forward in the passage quoted above. 



Schlosser seems not to have had access to a publication by 

 Biedermann in which ' Lagomys Oeningensis, II. v. Mey.,' from the 

 lignites of Elgg, near Winterthur (Switzerland), is described and 

 figured.'^ The description is somewhat insufficient, and so are the 

 figures, the details of the triturating surface of the molars not being 

 described or represented. Still, enough is given to allow of a 

 definite conclusion. A fifth lower molar is said to be present, 

 smaller than in Lepvs, and not, as in the latter, composed of two 

 columns or prisms. The two upper figures of mandibular rami 

 in figs. 2 and 3, pi. iii, which represent clearly the outer side, show 

 in the anterior cheek-tooth (p. 2) two lateral grooves, which are 

 characteristic of this tooth of Lagojjsis verus. This character, as 

 well as the evident rootless condition of the cheek-teeth, enables us 

 to exclude at least the figured specimen of Titanomys Fontannesi 

 (Dep.), which might otherwise need consideration, being of about 

 the same size as Lagopsis verus and also on account of its occurring 

 elsewhere associated with the latter. In one of his two splendid 

 memoirs on the Miocene Vertebrates of the Ehone Basin, Deperet 

 has described and figured, from the Middle Miocene of La Grive- 

 Saint-Alban, a mandibular ramus exhibiting the characteristic 

 anterior premolar of Hensel's Lagomys verus, and provided besides 



1 Loc. cit., p. 32. 



2 "W. G. A. Biedermaun : Petrefacten aus der Umgegend von "Winterthur, 2^'^^ 

 Heft, Die Brauukolilen von Elgg, p. 13, pi. iii, figs. 1, 2, 3 (1863). 



