280 Annals of the South African Museum. 



measures 146 mm. across. From the upper margin of the foramen 

 magnum to the highest point of the skull is 150 mm. The foramen 

 magnum itself measures at its narrowest part in the neighbourhood 

 of the hypoglossal foramen 32 mm. by 42 mm., while the width 

 across the occipital condyles is 116 mm. 



The specimen was discovered by Mr. C. J. de Villiers in the banks 

 of the Modder Eiver, half-way between Kimberley and Bloemfontein. 



As it differs from any of the recent species and also apparently 

 from any of the previously known extinct forms, I propose to name 

 it B. prisons . 



In the outward spread of the horns it resembles more the northern 

 forms, such as B. cokei or B. swaynei, but differs markedly from both, 

 especially in the greater size and in having much more massive 

 horns. Pomel has recently described two new extinct species from 

 North Africa under the names Boselaplius probabalis and B. ambigmis. 

 Both of these resemble this South African form more closely than 

 any of the recent species, but both differ in the curve of the horns. 



