188 DR. C. J. FORSYTH MAJOR ON MIOCEKE SQUIRRELS. [Feb. 28, 



auhinnii), presents a closer approximation towards the hystricine 

 type in the relatively large infraorbital opening \ 



Again, another gronp of Ethiopian Squirrels (Sc. rnfohmcliiatus, 

 8c. anmilatus, Sc. punctatw^, >Sc. shirensis), heloBgmg to the /Sciurvs- 

 vH](/((rls-tyi^e by the characters of their dentition, show in the 

 conformation of their skull some approach tov\ ards Xtrus ; whilst, 

 on the other hand, a few species, which from the form of their 

 skull cannot be separated from the A^yi's-group, tend by the cha- 

 racters of their molars somewhat towards the Sciuriis-ruh/aris- 

 type, as, for example, amongst Oriental Squirrels the Sc. ii'lstr'i(Un.<t 

 and Sc. [xdmanuiu 



If we try to express by a systematic arrangement these various 

 relations, two courst^s appear open to us : either to unite Xerus 

 with fScitii-Ks, or to create separate genera for those groups of 

 species \\hich depart from Scitu-us in approaching Xervi. However, 

 neither of these two suggestions seems satisfactory. By uniting 

 Xenis with S'chirus this last genus would become still more 

 heterogeneous than it is already — Xems, sensu stricto, having 

 besides near relationships with Spemiophilvs. By splitting up 

 Sciunis in Aarious genera, the relationships of these last to Xems 

 would not be seen in their true light. So that it appeared to me 

 more rational to adopt a middle course, viz., to detach irom Scium^ 

 a certain number of species, which in their skull and dentition 

 show Xeroine afBnities, and to unite them M'ith Xcrus, \Ahich last 

 genus u'ould thus become composed of fi\e subgenera (see the 

 table on the opposite page). 



The genus 8chii'H,s, chstinguished from Xems by characters 

 of the skull as well as of llie dentition, is di\ ided into three 

 subgenera, each of w hich is characterized by cranial and dental 

 peculiarities. 



Subgen.fl, Eoscinruit, contains the Oriental Giant Squirrels, which 

 by all authors on the subject, with the exception of Anderson, 

 have been recognized to be a distinct group ; in 1842 P. G-ervais ■ 

 pointed out the characters of the skull. As I have already 

 stated more than onc(^ the molars are perfectly brachydont, with 

 delicate rugosities of th(> enamel-covering. Only one superior 

 premolar. 



Jn the subgenus h. >Scivnis we have four diAisions : — (a) A small 

 group of Ethio])ian Squirrels, characterized by the absence of the 

 minute superior premolar, and, as a compensation, a Aery elongate 

 ])osterior premolar. On the rest, the dentition is similar to that of 

 Sc'iKrns v%d(j(iris. I have before described the slight differences in 

 the molar pattern of division ft, containing the majority of so-called 



' Their skull in general, and most of all that of Sc. ebii, is so strikingly 

 X«v^ii-like, witli tlie only exception of the jugalia not being depi'essed, that it 

 seems not possible to maintain them in the genus Sciurus if Xems be 

 maintained as such. 



" P. Gervais, "Description de I'Ecureuil Delessert, accoinpagnee de quelques 

 remarques sur la famille des Eongeurs seiuriens,"' Magasin de Zoologie, 2. iv. 

 l!^42, p. 4. 



