462 Zoological Society : — 



In its slender proportions, and the relative positions of the pro- 

 cnemial and ectocnemial ridges, the tibia of the Dinornis struthioides 

 agrees with that of the B. dromioides. 



Description of the Bones of the Leg of the Dinornis gracilis. 



The advantage of additional specimens, as confirming, by the repe- 

 tition of the same characters, a species previously defined, is still 

 greater in respect of the ground which they afford for the discrimi- 

 nation of a distinct but nearly allied species. Notwithstanding the 

 well-marked differences observable between the femur of the Dinornis 

 struthioides and the Dinornis gracilis^ I might have deemed them 

 due to differences of sex or individuals, had I not had evidence of the 

 fixity of the specific characters of the Dinornis struthioides by the 

 successive arrivals of additional specimens of its bones. Attending 

 the hoped-for confirmation from such arrivals, it appeared to be 

 most prudent to refrain from announcing a new species of the rapidly 

 increasing family of the great wingless birds of New Zealand until 

 further confirmation might be obtained by corresponding differences 

 in the tibiae and metatarsi of the two species. 



Having had the good fortune at length to obtain these additional 

 illustrations of the Din. gracilis, I no longer delay communicating 

 descriptions and figures of them to the learned Society, in whose 

 Transactions my former Memoirs have appeared and have been so 

 liberally illustrated. 



Femur. 



The following are the chief dimensions of this bone : — 



in. lin. 



Length 11 2 



Breadth of proximal end in the axis of the neck . 3 10 



Breadth transverse of distal end 4 



Circumference of middle of shaft 4 8 



A small portion of the upper ridge of the great trochanter has 

 been broken off: when entire, the femur of the Din. gracilis presents 

 the average length of that of the Din. struthioides, but it is more 

 slender in proportion, the head is smaller, and is supported by a 

 better-marked constriction or neck, especially at its under part. The 

 upper platform of the trochanter is narrower, the anterior border of 

 the trochanter not being extended so far forwards and outwards. 

 The angle between the upper and fore surfaces of the trochanter is 

 a right one, and they meet at a sharp ridge. The rough oval surface 

 between the head of the femur and the base of the trochanter is 

 smaller than that of the Din. struthioides. The outer irregular sur- 

 face of the trochanter is of much less breadth in the Din. gracilis. 

 The muscular impressions at the sides of the shaft meet and form a 

 longitudinal ridge along the back part of the middle third of the 

 shaft : they are separated by a tract of half an inch in the Dinornis 

 struthioides, and terminate below in two tuberosities. The corre- 



