NO. 8 NEW AFRICAN UNGULATES HELLER 1 3 



long, triangular, the sides posteriorly extending out to edge of ante- 

 orbital fossa, and forming part of roof; supraorbital pits large; 

 lower edge of anteorbital fossa formed into a sharp knife edge, ter- 

 minating in a prominent masseter knob ; mesopteryoid fossa ending 

 in a sharp obtuse angle, and well behind lateral fossa, which are 

 rounded and terminate on a line with middle of first upper molar; 

 bullae large, long and narrowed on lower surface into a sharp ridge ; 

 tooth-row long, equalling distance from first premolar to tip of 

 premaxillse; inner margin straight. 



Measurements. — Head and body, q6o mm.; tail, 80; hind foot, 

 280; ear, 107. 



Skull: Condylo-basal length, 166; basilar length, 155; interorbital 

 width, 51 ; zygomatic breadth, 74; nasals, 74 x 29; diameter of orbit, 

 32 ; length of upper tooth-row, 53 ; first premolar to premaxillse tip, 

 53 ; length of bullae, 22.5. 



Horns: Length on curve, right, 112, left 114; circumference at 

 base, right, 52, left, 50. 



The races of Ourebia are strikingly alike in color and size, but 

 most of them inhabit widely separated areas, and are well delimited 

 geographically. The skull-variation is really immense and very little 

 dependence can be placed on such characters. The horns, however, 

 show good average characters as regards their slant, size and shape, 

 but these are all quite slight and only appreciable as averages. The 

 series from the Upper Nile shows very little color-variation, and 

 much less skull-variation than the series of cottoni from the Guaso 

 Ngishu Plateau. The difference between this race and cottoni is 

 surprisingly slight, notwithstanding the fact that these two races 

 live at the extremes of the vertical range of the genus. 



OREODORCAS, new genus 



Type; Redunca fulvoniftda Afzelius. 



Characters. — Tympanic sheath which encloses the tympanohyal pit 

 low, and not extending downward on sides of bullae ; knobbed pro- 

 cesses of basioccipital small and short ; facial portion of lachrymal 

 bone long and narrow and extending far posteriorly on orbit, well 

 behind termination of nasal bones ; orbit large, the vertical diameter 

 one-half length of nasal bones ; infraorbital opening situated pos- 

 teriorly, above anterior end of middle upper premolar ; masseter 

 knob on sides of maxillary small ; pit at base of condyles posterior 

 to bullae deep ; lachrymal-nasal sinus narrow ; premaxillae long, 

 length one and one-fourth times in nasal length. 



