PROFESSOE OWEN ON THE GENUS DINOllNIS. 251 



In the immature individuals of Dinornis, not much exceeding in size tlie present 

 mature example of D. parvus, the proximal epiphysis is seen to consist chiefly of the 

 epicnemial process with the upper portions of the procnemial and ectocnemial ridges ; 

 the epiphysis, also, includes the outer of the two tuberosities for the attachment of the 

 intercondylar ligaments. The broad articular surface for the inner femoral condyle, 

 and the tuberosity for the outer one, are formed by the diaphysis. 



The distal epiphysis of the tibia includes both condyles of the articular pulley, 

 including the whole articular surface, and also that portion of the shaft which forms 

 the outer (fibular) wall of the canal for the extensor tendon, including the tuberosity 

 giving attachment to the same end of the ligamentous bridge, which subsequently 



becomes ossified. A foramen marks the remnant of the outer (fibular) part of the 

 suture between the diaphysial process of the epiphysis and the rest of the shaft of the 

 tibia. The anterior extension of the epiphysis, for a considerable extent upon the 

 diaphysis, is shown in fig. 4, pi. lix. of the Memoir on Dinornis gravis ', and negatives 

 the homology of this characteristic avian epiphysis with the ' astragalus,' or other 

 proximal tarsal bone in Eeptiles. From the distal epiphysis is developed the groove 

 and bridge for the tendon of the ' tibialis anticus.' 



§ 10. Patella. 



Only in the present complete skeleton have I found the patella of a Dinornis pre- 

 served (PI. LVIII., bones of the right leg). It is an oblong triedral bone, the outer or 

 front side being the broadest, slightly convex, and rather rough ; the other two sides 

 are smooth, as if originally coated by cartilage. The surface next the outer femoral 

 condyle is moderately sinuous ; that next the inner condyle is flat transversely, concave 

 lengthwise at the proximal two thirds, convex to the deflected small end. The length 

 of the patella is 1 inch 1 line, its breadth 7 lines. 



§ 11. Fibula. 

 The proximal end of the fibula (PI. LVI. fig. 7) contributes, as in other birds, to the 

 articulation with the outer femoral condyle; its breadth is 1 inch 4 lines. On its 

 inner (tibial) side the articular surface (ib. a) is continued upon the shaft for an extent 

 of 4 lines. Below this part the bone rapidly contracts, takes on a triedral form, the 

 hinder and inner angle articulating with the fibular ridge of the tibia. On the opposite 

 side of the bone is an elongate rough surface for the origin of the ' peronseus medius ' 

 muscle ^ Beyond the tibial conjunction the fibula more rapidly contracts, and termi- 



' Trans. Zool. Soc. vol. viii. 



' ' Accessorius flexoris digitorum,' Ticq d'Azyr. See "Anatomy of the ApUryx," part ii. (Myology). Trans. 

 Zool. Soc. vol. iii. p. 297, pi. xxxii. fig. 1, 12. 



2q2 



