366 Dr. C. I. Forsyth Major — Some Rodents from Oeningen. 



previously figured by Konig, had been assigned by the latter to the 

 genus Anoema, under the name of Anoema Oeningensis} 



In his first note on the Lagomys-XW'ie Rodents of Oeningen, 

 Hermann von Meyer was not aware that more than one form is 

 represented in the deposit ; accordingly, he comprises all the 

 specimens under the name Lagomys Oeningensis.^ Later on, in his 

 monograph of the fossil Vertebrates of Oeningen,^ he arbitrarily 

 sets aside Konig's specific name of the smaller form, for which he 

 adopts a manuscript name by Von Tschudi, founded on one of 

 the labels, and applies the name Lagomys Oeningensis to the larger- 

 sized specimens. 



In a memoir read before the Linnean Society, and which will be 

 published about the same time with the present note, I have at 

 length dealt with the smaller form, whose proper name will be 

 Prolagus Oeningensis (Kon.), but with which we have not to deal 

 here. However, the Oeningen specimens of Rodents under examina- 

 tion having, from their unsatisfactory condition, occasioned much 

 of the prevailing confusion, it is necessary before making an 

 examination of the fossil in tlie British Museum, which I have 

 determined as Logopsis verus, to glean whatever additional informa- 

 tion we are able from other fossils of the same and contempoi'aneous 

 deposits. 



Two skeletons from Oeningen are ascribed to 'Lagomys Oeningensis'' 

 in the " Fauna der Vorwelt " — one from the Carlsruhe Museum, on 

 pi. ii, fig. 1 ; the other from the Seyfried Collection at Constance, on 

 pi. iii, fig. 1. Both agreeing approximately in size, H. v. Meyer 

 assumes as a matter of coui'se that they belong to the same species. 

 The former specimen affords no evidence as to the important 

 characters of the number and form of the cheek-teeth. In the latter 

 the number of the lower cheek-teeth is given as four, the writer 

 adding that neither is the posterior tooth tripartite as in recent 

 species of Lagomys, nor does the shape of its alveolus favour such 

 an assumption. H. v. Meyer was under the erroneous belief that the 

 recent Lagomys had only four lower cheek-teeth, the posterior one 

 complicated by the addition of a third lobe. As a matter of fact all 

 the members of the recent genus Lagomys have five lower cheek- 

 teeth, the fourth being bipartite like the two preceding it in the 

 series, whilst the fifth is a small simple cylinder. 



The insufficient acquaintance with the dentition of Lagomys 

 prevented H. v. Meyer from investigating if pei'chance in the 

 Seyfried specimen there was an alveolus for a fifth cheek-tooth. 

 This omission and the error by which it was engendered have both 

 proved fatal. 



H. V. Meyer's error as to the number of teeth in Lagomys was set 

 right by Hensel * ; the former author was thereby induced to transfer 



' Kouig: Icones Foss. Sect., pi. x, fig. 126 (1825). 

 ■•^ Neiies Jahrbuch, p. 58 (1836). 



^ H. V. Meyer: " Zur Fauna des Vorwelt, Fossile Saugetliiere, Vogel imd 

 Eeptilieu aus dem Molasse-Mergel vtn Oeningen," p. 7 (1845). 

 * Zeittchr. deutsch. geol. Ges., viii, p. 698 (1856). 



