FREE INSTITUTE OF SCIENCE 



45 



RHINOCEROS 



Tibia. — The short, massive tibia, plate xv. fig. 5, is represented by five 

 complete examples and portions of several others. These are all adult, and 

 very closely resemble the tibise oS. fossiger. The external condylar articulation 

 is, as a rule, not quite so pointed anteriorly and not so triangular in shape as 

 the corresponding part of the tibia oi fossiger, but this is a point of little value. 

 It is apparently not uncommon for the fibula to ankylose with the tibia in 

 fossiger, but no specimen of protenis presents this peculiarity. 



Subjoined are measurements of several tibiae : 



Measurements of the calcaneum are as follows : 



Extreme length . . .202 mm. .220 mm. .247 mm. .220 mm. .250 mm. .270 mm. 



Width, posterior part of 



proximal end . .100 " .115 " .105 " .103 " .112 " 



Width, anterior face of 



distal end . . .73 " .78 " .80 " .78 " .78 " .82 " 



Tarsus. — The calcaneum, plate xi. figs, i and 2, is noteworthy for the 

 roundness of the calcaneal projection, the vertical and transverse measure- 

 ments of the body of the bone differing but little, whereas in R. imicornis the 

 vertical measurement much exceeds the transverse. 



The astragalus, plate xiii. fig. 4, is wide and low, the tibial groove shallow, 

 the cuboid articulation wide; these conditions being the reverse of those found 

 in R. unicornis. There is nothing to distinguish the two bones just described 

 from the corresponding bones oi fossiger. 



The various facets of both astragalus and calcaneum exhibit a wonderful 

 amount of variation, and two specimens could readily be selected which might 

 well be considered as belonging to two distinct species, were not every inter- 

 mediate condition present. For distinctive purposes the shape and, to a great 

 extent, the arrangement of these facets must be considered worthless. 



Aphelops malacorhimis 



Rhinoceros longipes was described by Dr. Leidy in the " Proceedings of the 

 Philadelphia Academy of Sciences" for i8go, page 183, where descriptions and 

 measurements are given of a lower canine and second and fourth metacarpal, 

 and it is noted that other bones and teeth were contained in the collections 



