16 
specimens being only from 26 to 30 inches in length, and the longest 
recorded only 35, 
Female similar to the male, but the horns more slender, smoother, less 
heavily ridged, and less strongly curved backward, and neck and body less 
robust. 
Hab. Africa south of the Sahara, except in the Congo wood-region. 
It is a well-known and generally accepted fact amongst naturalists that 
animals which have a wide distribution have also a special tendency to vary, 
and that if specimens of them from different parts of their ranges are com- 
pared, such specimens are usually found not to agree exactly, but to be 
distinguishable by differential characters more or less evident. When these 
characters are easily observable and definable their possessors are usually 
referred to different species, which are supposed to ‘‘ represent” one another 
in their respective areas, and are hence often called ‘‘ representative species.” 
When the distinguishing characters are slight and less easily recognizable it 
has recently become the practice, especially among American naturalists, to 
designate their possessors as “‘ subspecies,” and, in order to indicate this, to 
add a third “ subspecific” name to the ordinary generic and specific terms. 
This plan we have already adopted in some cases in the present work. But 
there are many cases in which, either from imperfect evidence or from an 
insufficient supply of specimens, it is very difficult to decide whether a 
‘local form,” as it may be termed, is better treated of as a species or as a 
subspecies. And in the present instance we have one of these cases before 
us. The Roan Antelope is very widely distributed in Africa. From the 
Cape Colony it extends all up the eastern side of the continent to British 
East Africa and Sennaar, and is also found on the west coast in Senegal, 
Togoland, Nigeria, and Angola. Specimens from all these countries present 
a very general resemblance, and have been considered by most authorities to 
be identical. On the contrary, other writers have regarded the local forms 
as distinct, and have separated them under different specific names. We 
confess that we have not been able (mainly, no doubt, from lack of sufficient 
specimens to consult) to come to a satisfactory conclusion on this subject ; 
but, for the present, we think it a more prudent course to treat the local 
forms of this species found in the different districts of Africa as only of 
