4 PROFESSOR OWEN ON THE GENUS DINORNIS. 



low rough protuberance projects forwards and outwards below the antero-internal angle 

 of the entocondyloid surface ; between this protuberance and the opposite angle the 

 anterior surface is gently concave from side to side : the fossa between the proximal ends 

 of the ento- and ecto-metatarsals commences two inches below the intercondyloid 

 eminence : it is a vertical elongated ellipse, bounded behind by the mesometatarse, and 

 below by the rough depression and protuberance, for the insertion of the Tibialis anticus. 

 Below this protuberance a broad and very shallow depression extends to near the middle 

 of the shaft, where it is filled up by the advance of the mesometatarse towards the 

 anterior surface of the bone, where it forms a longitudinal prominence, which increases in 

 breadth as it approaches the condyle of the same element : a shallow and longitudinal 

 groove extends on each side of this median eminence to the interspaces between the 

 middle and the lateral condyles. There is no perforation in either of the grooves leading 

 to these interspaces. 



The back part of the upper two-thirds of the shaft of the mesometatarse forms a 

 buttress-like prominence extending from the mesocalcaneal process down to the lower 

 third of the common shaft ; the upper third of this process is very rugged ; the rest is 

 comparatively smooth : the borders of the back part of the common shaft are roughened 

 for the attachment of the strong fascia that bound down the tendons traversing that 

 aspect of the shaft : the rough tract on the inner side terminates in the rough oval 

 depression for the attachment of the rudimental metatarse of the hallux : from the lower 

 border of this depression to the division between the inner and middle condyle measures 

 two inches eight lines ; the relative position of the depression being the same as in the 

 Apteryx. 



The distal trochlear or condyloid extremities of the three coalesced metatarsals ter- 

 minate at different distances from the proximal ends of the bones, the outer one being 

 the shortest- — not the inner one, as in the Apteryx ; and the middle one, as in most birds, 

 being the longest and the most prominent one anteriorly. The inner trochlea (ii) pre- 

 sents a depression on its inner surface and another on its under surface, from which a 

 shallow channel is continued a little way backwards upon the back part of the condyle 

 and forwards upon the broad anterior convex articular surface : this surface slopes 

 obhquely from the outer to the inner margin of the trochlea : the inner part of the hinder 

 surface of the trochlea is the most produced : the outer surface of the condyle presents 

 a wide and deep depression. 



The articular surface of the middle trochlea is narrowest at its posterior commence- 

 ment, gradually expands to its lower and fore part, and contracts, but in a less degree, 

 to its anterior boundary : it describes three-fourths of a circle, and is grooved along its 

 middle, the groove widening towards the posterior part of the bone. The outer portion 

 of the posterior boundary projects from the level of the short stem of the condyle : the 

 anterior boundary rises very gradually but somewhat obliquely from the level of the 

 stem : the sides of the condyle are widely and deeply excavated for the lateral ligaments. 



