74 



EINAR LÖNNBERG, MAMMALS COLLEOTED IN CENTRAL AFR1CA. 



somewhat different. C. g. emini lias not quite as large teeth as this one, but larger pa- 

 latal foramina. It is, however, possible that the smaller size of the molars of the type 

 is due to wearing, and the otlier characteristics variable, therefore I \vill not deny that 

 this specimen may possibly belong to the race named Cricetomys gambianus emini 

 Wroughton. 1 



Still greater difficnlties arise for the identification of the small-toothed specimens, 

 which are five in nnmber, not connting an extra skull. With regard to colour they agree 

 on the whole very well with C. g. dolichops Osgood. The latter appears, however, to 

 have a longer and dif f erently shaped skull with a very elongate preorbital portion result- 

 ing in much longer nasals and diastema. The palatal foramina are very short in dolichops, 

 only measuring 7,5 mm, although the type was an adult male. 



From C, g. dichrurus Osgood, which also is small-toothed, the Masisi specimens 

 dif f er sharply by their pure white belly. The type of dichrurus was an »adolescent fe- 

 male», and therefore the cranial measurements recorded by Osgood cannot be directlv 

 compared with those of a f ully adult specimen such as that from which the above recor- 

 ded dimensions have been taken. To throw some light on the gradual development of 

 the skulls the following series of measurements is added. 



9 »n:o 155» 



9 »n:o 158^ 



»n:o 153» 2 



58,2 mm. 



62,5 mm. 



70,3 mm. 



54,5 » 



58,5 » 



67,7 » 



27 » 



26,8 » 



31,5 » 



22 » 



22,2 » 



28 • 



9,8 » 



9,4 » 



10,2 » 



17,3 » 



19 » 



22 » 



7 » 



7,5 » 



8,2 » 



10,4 » 



10,4 » 



11 » 



3,2 » 



3,2 » 



3,5 » 



9 » 



8,5 » 



10,4 » 



Greatest length of skull 



Condylobasal length of skull 



Zygomatic breadth 



Nasals 



Least interorbital breadth 



Diastema 



Palatal foramina 



Upper molar series 



Breadth of ra 1 



Transverse diameter of preorbital portion . . 



These measurements prove that the preorbital portion of the skull with nasals 

 and diastema are even comparatively speaking shorter in the young than in the adult. 

 Osgood's »adolescent female» of dichrurus has consequently not yet attained full size 

 in this respect, and the diagnose must thus be read with regard to this fact. The thick- 

 ness of the preorbital portion of the skull appears to increase rather irregularly, or to 

 vary individually. 



C. g. dichrurus is said to have »extremely small bullse». The specimens of this 

 collection prove that the bullse of the small-toothed race certainly are less inflated than 

 those of the large-toothed emini-grovp. »Extremely small» is, however, too strong an 

 attribute for the bulla 1 of the specimens now in question. 



1 From C. g. proparator Wroughton if differs in having hands and feet dark, and less white on the tail, dark 

 under fur etc. 



2 No skin! 



