348 SCOTT. [Vol. XI. 



and the external linea aspera is much better marked and longer. 

 The pit for the attachment of the plantaris muscle is larger 

 and deeper, but has not such a rugose bottom and is not so 

 conspicuous when viewed from the side, which is due to the 

 fact that in the musk-deer the outer wall of the pit is cut away. 

 The rotular groove is very different from that of MoscJius. In 

 the latter the groove is narrow, symmetrical, with borders of 

 equal height and thickness, and continued well up upon the 

 anterior face of the shaft, while in Protoceras we find a con- 

 dition more like that of the larger deer, though not in the same 

 degree of development. In this genus the trochlea is broad and 

 shallow ; the inner border is considerably higher and thicker 

 than the outer and the articular surface is reflected over upon 

 the mesial face of the bone ; but there is no such vertical pro- 

 longation of the groove upon the shaft. The characteristic 

 rotular trochlea of the tragulines, which is also found in 

 Leptomeryx, is quite different from that of Protoceras, which 

 in this respect approximates more to the higher Pecora. The 

 condyles are narrow and project less behind the plane of the 

 shaft than in MoscJius, more than in Tragiihis. 



The Patella (PI. XXII, Fig. 15) is remarkably large in pro- 

 portion and somewhat peculiar. It is of the same general 

 shape as in the musk-deer, broad above and tapering below to 

 a blunt point, but is more massive and rugose and larger in 

 every dimension. The fossa for the inner border of the femoral 

 rotular groove is more deeply impressed than that for the outer 

 border, and its internal edge forms a prominent projection, 

 which extends along the mesial face of the femur. There is 

 considerable individual or perhaps specific variation in the 

 shape of the patella. One specimen is broader and less taper- 

 ing than the one above described, and its inner prominence is 

 not so much produced. 



Both specimens of the Tibia (PI. XXII, Fig. 16) in the col- 

 lection have lost the distal end, but fortunately this is pre- 

 served in Osborn and Wortman's material. Though longer 

 and heavier than the tibia of Moschus, that of Protoceras is of 

 essentially the same character. The condyles for the femur 

 are rather narrow, but well extended from before backward ; 



