474 Mr. 0. Thomas on the 



of this group. Postorbital processes much reduced, directed 

 backwards. 



Cheek-teeth ^ ; p^ disproportionally small as compared with 



the large 2>*, which is of nearly the same size as the molars. 



Molars highly hypsodont. 



Range. West African Forest region, extending eastwards 

 into British East Africa. 



12. MrOSCIURUS. rr 



Type. 



Genus novum M. mmutus 



•{Sciurus minuttis, de Chaillu). 



Size very small, the single species not larger than a house- 

 mouse. 



Skull as in the Oriental Nannosciurus, with the exception 

 that the ectopterygoid is aborted and the tooth-row is a little 

 further back, the lower edge of the zygoma-root coming 

 opposite the premolar instead of the anterior or middle molar. 



Cheek-teeth - as against - in Nannosciurus. 



Molars smaller than in Nannosciurus, but similar in 

 structure. 



Range. West Africa (Gaboon). 



The absence of p^, present in all the Asiatic Nannosciuri', 

 and the suppression of the ectopterygoid, well-developed in 

 the members of that genus, as in nearly all other squirrels, 

 indicate that the African Pigmy Squirrel should be separated 

 generically from its Asiatic allies. 



The following is a list of the African Squirrels placed in 

 their respective genera. The species are arranged alpha- 

 betically in each genus. Forms which have been described 



had not seen, but was merely quoting from Geofiroy) was said to be 

 " perhaps a species of my genus Tenotis ...."; and the rule (' Science,' 

 1907, p. 521; says distinctly {e. y) that a species which the author 

 doubtfully refers to his genus cannot be taken as the type of it. Nor 

 can Tenotis be taken as a monotypic genus (rule c), though " T. griseus " 

 is the only species mentioned, lor the genus is distinctly formed for 

 " all the squirrels with pouches ...."; so that all the pouched squirrels 

 known in 1817 would have been included in it, and it would have been 

 equally valid had the doubtfully included T. griseus not been mentioned. 



Secondly, the deiinite quotation of Tenotis as a synonym of Tamias by 

 Allen (Mon. N. Am. Rod. p. 779, 1877) appears to me in such a case 

 to bear the authority of a " first reviser,'' and so to settle the question. 



I fail to see any reason why Geoffrey's obvious misprint of " enjthopus " 

 should not be corrected into erythropus. 



