154 PROFESSOR OWEN ON THE GENUS DINORNIS. 



comparison of the nietatarse of Dinornis elephantopus with that of its nearest congener 

 the Dinornis crassus, the following differences present themselves. The entocondyloid 

 depression (fig. 2, e) is deeper, its fore-and-aft diameter is greater, and its transverse 

 diameter less, than in the ectocondyloid one, c ; but the breadth of the entocondyloid 

 depression is relatively greater and its depth somewhat less in Dinornis elephantopus 

 than in Dinornis crassus. 



The transverse convexity dividing the two condyloid depressions is relatively broader 

 in Dinornis elephantopus ; and the rough surface external to the anterior intercondyloid 

 prominence is more strongly marked. 



The two calcaneal ridges present an equal prominence in Dinornis elephantopus : the 

 ectocalcaneal one, c e, is the most prominent in Dinornis crassus. 



The anterior surface of the metatarsus differs chiefly in the proportions indicated in 

 the "Table of admeasurements," p. 153, from that in Dinornis crassus: like most of 

 the metatarsi of that species, one or more vascular foramina occur above the subcir- 

 cular rough surface of insertion of the flexor pedis, which occupies the lower part of 

 the shallow depression on the upper and fore part of the shaft. 



Along the lower half of the shaft the median longitudinal and progressively widening 

 prominence, due to the middle of the coalesced metatarsal bones, is rather more marked 

 than in Dinornis crassus. 



The inner side of the shaft is marked at its upper half by the oblique rough tract 

 indicative of the insertion of the powerful aponeurosis of the gastrocnemic muscles. 

 At the back surface the upper part of the mesometatarse is relatively less prominent 

 than in Dinornis crassus. 



The two vascular foramina occupy corresponding relative positions. All other 

 notable differences are those of size and proportion. 



From the metatarsus of Dinornis rohustus that of the Dinornis elephantopus differs, 

 most strikingly, in its proportions of length to breadth, being little more than half the 

 length, but of nearly equal breadth ; the distal trochlese, however, being relatively less 

 expanded than in Dinornis rohustus. 



The anterior vascular perforation is less than in Dinornis rohustus : the inser- 

 tional roughness for the tibialis anticus below the foramen is of equal size. The upper 

 half of the fore part of the metatarsus is longitudinally channeled in Din. rohustus, 

 not in Din. elephantopus. The corresponding part of the back part of the shaft is 

 much more prominent in Dinornis rohustus. The characteristics of the metatarsus 

 of Dinornis elephantopus are more strongly manifested in the comparison with that of 

 Dinornis giganteus\ of which bone it has only half the length, other dimensions being 

 equal or even greater in Din. elephantopus. 



Of the depression, - which is very faint in Dinornis rohustus, — for the ligamentous 



' Trans. Zool. Soc. vol. iii. pi. 27. fig. 1. 



