IS 93.] DB. C. J. FORSYTH MAJOR ON MIOCENE SQUIRRELS. 193 



of the outer cusps. A siiuikir shupe is s1io\au by the outer cusps 

 of tSciui'opterun 2)enrsoHi, and by those of Pseudosciwus, which I 

 haAe loug ago ^ described at length, in dra^^■iug the attention to 

 their various analogies with Ungulates. These analogies are so 

 decei\ing, tliat the discoverer of PscHdosciurus, having but isolated 

 teeth at his command, considered them to be from an Ungulate. 



T\Ao lower molars of a Eodent from the Phosphorites of 

 Mouillac have been described by tSchlosser under the name of 

 I'Sciurodoii-. He compares them with Pteronujs, and suggests that 

 they are nearly related to, and perhaps identical with, the Oregon 

 Menisconujs ^. 



In the British Museum are preserved se\ eral unpublished isolated 

 molars of a minute-sized Kodent from the Oligocene Bembridge 

 Limestone of the Isle of Wight, some of which, hkewise, can only 

 be approximated to ScmropU'rus or a nearly related genus. Similar 

 remarks apply to a molar from the Swiss Eocene of Egerkiugeu, 

 lately published by Kiitimeyer under the name of Alluravus \ which, 

 however, is undoubtedly a louer molar of a Rodent, and agrees 

 most \\ith those of the larger species of SciuropU'rus, although, as 

 stated above, it is somewhat intermediate between Fteroou/s and 

 Sciuropterus. Alluravus having relations to one of the species of 

 Phsiada^ns (PI. f/ervaisii, Lem.), from the Lower Eocene of Eeims ', 

 it results that >SciuroptefU'(-\ike Eodentia were very abundantly 

 represented and widely spread during the Tertiary. 



1 shall hereafter point out more fully the resemblance between 

 two recent species of Sciuropteri, Sc. horsfieldi and 8c. luarsoni, 

 with tlie two Eocene genera Sciiiroklcs and Pseadosciiirus. 



After this brief reference to fossils showing close analogy «'ith 

 recent Elying-Squirrels, it I'emains for me to justify my arranging 

 these last in a distinct subfamily, the Pteromyiace. 



Taking the genus PU'romi/s in a restricted sense, it is a very 

 homogeneous one, in its dentition as well as in the characters of 

 the skull. The Sciuropteri, on the contrary — mth which I 

 propose to unite Pteromys teiihromelas, Giinth., and Pt. plicmmdas, 

 Giinth. — show on closer examination such a variety in the shape 

 of their molars, that, if found in a fossil condition, they would 

 without hesitation liaxe beini assigned to four or five genera. All 

 of them are more or less brachydont, witli tlie exception of 

 Sciuropteriix rolans, L. sp., wliicli leans towards hypsodontisin; all 

 have in common an elegant sculpturing of the enamel, which gives 

 often a crenate appearance to the cusps or crests. J3ut, apart from 

 this, almost every species possesses a ])eculiar pattern of its molai's. 



' ' ?f ageriiberreste aus Bohnerzen Suddeutschlands unci der Scbweiz,' 1873. 



^ M. Schlosser, "Die Nager des eiiropiiischen Teitiiirs," I.e. pp. Ul(73)- 

 '.i;3(7j), pi. vii. (ii.) figs. 0, 10. 



^ Z,.c. pp. Ui, 14«, 154. 



' L. Rutiiiieyer, "Die Eocaue Saugelliierwclt von Egerkingon " (Ziiricli, 

 1801), pp. VI4-'J8. pi. vii. fign. 18, 11». 



' Leiuoi no, "Etude d'ensemble sur lea donls doB Mainuiif'eres fbssiles des 

 environs de Reini.-i," Bull. Soc. Geol. France, t. xix. 1801, pi. x. fig. 05. 



Pnor. Zooi>. Soc.~1893, iNo. XIU. 13 



