198 
Pl. XXXV., is its smaller size, and the angular form of the posterior notch, which was 
rounded at the bottom in the larger sternum, as in the Apteryax. 
A distinct form of sternum, although evidently appertaining to a bird which was de- 
prived of the power of flight, is that which is represented in Pl. XLVIII. figs. 5-8. 
The specimen is part of the collection obtained by Mr. W. Mantell at Waingongoro, 
and which was sold by Dr. Mantell to the British Museum; where, for the facilities 
afforded for describing and figuring the specimen, I feel indebted to the kindness and 
urbanity of the learned Keeper of the Department, Charles Konig, K.H., and of his able 
Assistant Mr. Waterhouse. 
Its proportions would justify its reference to a bird of the size of that to which the 
skull', referred in the Memoir on Nofornis, p. 151, to that genus, has belonged ; and 
although its shape, so far as I at present know, is unique in the class of Birds, I con- 
ceive it to be a modification of that type which characterises the Rail and Coot tribe 
(Rallide). The grounds for this opinion will, perhaps, be best illustrated if I premise 
a description of the sternum of that existing species of the family in New Zealand, 
which, being incapable of flight from the shortness of its wings, I have referred to a 
genus called Brachypteryz. 
The sternum of the Brachypterya is almost as remarkable for its narrowness as in the 
Apteryx for its breadth. The anterior border has a deep rounded median emargination, 
between the projecting borders of which, and the more produced costal angles, the wide 
coracoid grooves are placed. The costal border occupies one-fifth of the lateral margin 
of the sternum and presents articulations for five sternal ribs: the narrow posterior 
border has a deep and moderately wide median emargination and two lateral, very narrow 
and very deep ones, like fissures, equalling one-third of the entire length of the sternum, 
the outer border of each fissure being a long slender filiform process. Two ridges com- 
mencing on the outer surface of the sternum behind the coracoid grooves, converge to 
support the fore part of a shallow keel which subsides before it reaches the posterior 
border of the sternum. The outer surface of the bone is slightly concave between the 
keel and the costal margins of the bone. The upper or concave surface of the sternum 
presents two pneumatic depressions behind the coracoid grooves. 
The sternum of the Notornis (Pl. XLVIIL. figs. 5 & 6) resembles that of the Brachypteryx 
in its elongated and narrow proportions, and in the rudiment of a keel which commences 
by two ridges converging from the inner ends of the coracoid grooves: but the lateral 
styliform appendages, and consequently the lateral fissures of the posterior part of the 
bone, are wholly wanting, and the intermediate part of the body of the bone is narrower, 
and gradually contracts to what seems to have been an obtusely pointed extremity: but 
this is broken in the specimen. The keel does not project so far from the surface of 
the bone as in the Brachypteryx. The coracoid grooves are more shallow, and the whole 
sternum, although its general form and proportions are indicative of a bird of the same 
* Zool. Trans. iii, p. 366. pl. 56. fig. 7. 
