Dr. C. I. Forsyth 3Iajor—Oii Fossil Dormice. 493- 



Miocene locality of La Grive-Saint-Alban (Isere, France) ; it is at 

 present preserved in the Geological Department of the British 

 Museum (No. M 5,299). In tins fossil the upper premolar, thoui^h 

 already reduced in size, is less so than in the recent species, 

 exhibiting four transverse ridges as against two in M. avellanarius. 

 M. 1 is not rectangular, as in the latter, but quadrangular. The 

 lengthening of this tooth in the recent species is not, as might have 

 been expected, brought about by an increase in the number of enamel 

 ridges — for there are five of them in avellanarius, seven in the fossil 

 — but by a widening of the interspaces between the ridges. In 

 the shape and pattern of m. 2 there is scarcely any difference 

 between the two ; AT. avellanarius exhibits seven transverse ridges, 

 the corresponding fossil tooth six complete and two abortive 

 ridges. M. 3 is the smallest of the true molars in both species. In 

 M. avellanarius there are six transverse ridges, more crowded 

 together than in the anterior molars ; the fossil tooth is not larger 

 than the recent, but it contains no less than twelve exceedingly 

 minute transverse ridges. Short intermediate ridges are present 

 near the outer margin of all the true molars of the fossil. The 

 length of the four cheek-teeth is 3| mm. 



In the conformation of the premolar and in the reduced size of 

 m. 1, the fossil form therefore approaches towards a more normal 

 condition ; it comes near Glis, which in its turn is intermediate 

 between Muscardiniis and Etiomys. But in the pattern of the molars, 

 and more especially of m. 3, the Miocene species is still more 

 specialized than the recent species of Muscardinus. 



The i-emains from La Grive are by no means the only ones known 

 of this species. Lartet has given the name Myoxus Sansaniensix to 

 the smaller of two dormice from Sansan. His description, which 

 I transcribe, is rather imperfect : " Petit Loir de la taille de notre 

 Souris domestique. La couronne de ses molaires est plus compliquee 

 de contours emailleux que celles du Lerot et du Muscardin, par quoi 



il se rapprocherait davantage du Loir proprement dit " ^ 



However, from the characteristic figures published by Gervais,^ and 

 from some remains presented b}' Lartet to the British Museum (Natural 

 Histor^r) — No. 33,274^ — it can be seen that the Sansan dormouse is 

 identical with the one from La Grive. Gervais' figures have met 

 with severe but quite unfair criticism from more than one of the 

 later writers on the subject, because these figures disagree with tlie 

 teeth of another form of fossil dormouse hereafter to be described, 

 which was wrongly held to be the species noticed by Lartet. 

 Lydekker is quite right when stating that the Sansan specimens in 

 the British Museum (Natural History) agree precisely with those 

 figured by Gervais.* 



The fragmentary remains from Sansan in the British Museum 

 afford information with regard to the alveoli of the cheek-teeth, 



1 Loc. cit. 



* Zool. Pal. fr., pi. xliv, figs. 14-19. 



3 See Cat. Foss. Mamm. Brit. Mus., part i, p. 224. 



* Lydekker, Cat. Foss. Mamm., part i, p. 224. 



