364 SCOTT. [Vol. XI. 



descended from it, and the skull being in some respects more 

 advanced than that of the deer, Protoceras can hardly be an- 

 cestral to that family. 



It is not at all likely that the Tragulina are descended from 

 Gelociis, the latter having a more advanced type of foot-struc- 

 ture and an odontoid process of the axis which has already 

 lost the conical shape. The connection with the true rumi- 

 nants was, therefore, in all probability by means of some form 

 as yet unknown, which was rather more generalized than 

 Gelociis. With the line terminating in the existing tragulines, 

 which, so far as we know, have always been confined to the Old 

 World, Protoceras can have but a remote connection, but just 

 when and how this connection was established cannot at 

 present be determined. There are, however, certain Ameri- 

 can genera which are usually referred to the tragulines and 

 which probably are more or less distantly related to that 

 group. These genera are Leptoineryx and Hypertragulus ; 

 they are much alike, and yet with such significant differences 

 as show that they are to be regarded as divergent branches of 

 the same stock. One is tempted on zoogeographical grounds 

 to assume a relationship to these genera on the part of Proto- 

 ceras. Leptomeryx has an entirely different type of skull from 

 that of Protoceras and one which closely resembles the struc- 

 ture of the traguline skull, differing merely in the concavity or 

 flatness of the occiput, the small size of the auditory bullae and 

 their freedom from cancellous tissue, and in the presence of a 

 fontanelle or vacuity between the frontal, lachrymal, and nasal. 

 The odontoid process of the axis is conical. In the dentition, 

 however, even in details, there is much likeness between this 

 genus and Protoceras. In the character of the limbs Lepto- 

 meryx is in many respects in advance of Protoceras ; thus, in 

 the manus the magnum and trapezoid are ankylosed and the 

 second metacarpal is excluded from the magnum. But the 

 scapula, ulna and radius, metacarpals and phalanges, are very 

 much alike in the two genera. Pelvis, femur, tibia, and fibula 

 do not differ in any important respect, but Leptomeryx has a 

 posterior cannon-bone and coossified cuboid and navicular. In 

 spite of the many differences, there is an undeniable likeness 

 of habit between Leptomeryx and Protoceras. 



