68 EINAR LONNBEEO, MAMMALS COLLECTED IN CENTRAL AFRICA. 



and »smoke grey» (363, 4). This grey is overlaid with a very pale shade of »deep bistre », 

 produced by the tips of the hair. The lower side of the lateral membrane is paler than 

 the upper, but darker than the belly. The hairs of the tail has about the same colour as 

 the upper side of the membranes. 



For comparison with this may be quoted the renewed description of the colour of 

 /. zenkeri which Prof. Matschie kindly has sent me in a letter, since the specimen had 

 been better prepared and dried. »Der Riicken ist gelblich isabelHarbig, nur wenig gel- 

 ber als Woodbrown in der Nomenclature of colours und hell fohrenholzbraun (Taf. 310, 1) 

 bei Oberthur und Dauthbnay, Repertoire de Couleurs. Auf der Unterseite hat I. 

 zenkeri eine deutliche gelbe Farbe, die ziemlich stark zwischen dem Grau hervortritt, 

 ein helles Olivengelb, das an den Korperseiten ins gelblich Olivenfarbene iibergeht. Nur 

 auf der Brust ist das Grau etwas deutlicher. » 



The Idiurus from Masisi is also larger than /. zenkeri. The hind foot of the former 

 measures, claws included, 17,6 mm. and s. u. 16,5 mm., while in the original description 



of /. zenkeri we read: »Hinterfuss 15 [mm.J; — • — ■ — ; Hinterfuss bis zur Vorder- 



seite der vorderen Sohlenballenreihe 11 » [mm.]. The latter measurement of the /cZwrits 

 from Masisi is in the present dry state 12 mm. while /. zenkeri was measured as an alco- 

 holic specimen. 



To judge from the skin the Idiurus from Masisi appears to have greater bodily size. 

 The present adult specimen measures as skin about 95 mm. from snout to vent. The ear 

 appears to have about the same proportions as in /. zenkeri. 



The skull of the new form is also larger. It is unfortunately damaged as the occi- 

 pital region behind sutura lambdoidea is missing, but without the same its length is 22 

 mm., that is just as much as the greatest length of the entire skull of /. zenkeri. Ac- 

 cording to a communication from JVEatschib the distance from sutura lambdoidea to tip 

 of nasals is only 19 mm. 



It was of great interest to find that the genus Idiurus has a distribution which 

 extends so far east as it hitherto was known only from Cameroon. This fact makes it 

 probable that members of this genus inhabits the whole West African forest region. 



Aethosciurus ruwenzorii vulcanicus Thomas. 



2 cTc?, 2 ?? from Masisi near Kivu, Febr. 1914. 



Heliosciurus rufobrachiatus semlikii Thomas. 

 5 c^d", 2 ?? from Beni, Aug., Sept. 1914; 1 ? ibid., Jan. 1914. 



Heliosciurus rufobrachiatus arrhenii n. subsp. 



3 ^<S, 3 ?? from Masisi near Kivu, Febr. 1914. 



These Squirrels resemble H. r. semlikii from Beni, but differ from the same in being 

 considerably darker and larger. The back, especially its posterior portion is strongly 



