HuTTON.— 0?i tlie Moas of Netu Zealand. 103 



published measurements of all the bones found by him near 

 Whangarei/'^ which proved the same thing for C. curtus. 

 Nevertheless, Sir Julius repeated his statement in 1879 with- 

 out referring to either of these lists of measurements ; and in 

 1886, in his paper on D. oiceni, he once more says that there 

 are two different sizes in that species, f But again he gives no 

 measurements in proof of his statement ; and the extensive 

 table which I have compiled of the measurements of C. curtus 

 and C. oiveni, as well as of several other species, shows posi- 

 tively that they are not divided into two distinct sizes differing 

 either in the length or in the robustness of their limbs. 

 Certainly I admit tv^'O varieties, differing in size, in S. casua- 

 rinus ; but the sizes overlap one another, and have been re- 

 cognised only because they have a different geographical 

 distribution ; which is, by itself, a sufficient proof that they 

 cannot be the sexes of one species. 



I do not, of course, maintain that there was no difference 

 in size between the sexes. In the ostrich, the emu, and the 

 cassowary the male is rather larger than the female ; but in the 

 kiwi the female is considerably larger than the male. Pro- 

 fessor T. J. Parker has shown that in the kiwi the hind limbs 

 undergo a relative diminution in size between the time of 

 hatching and the attainment of fully adult proportion s,| and 

 this is especially the case with the female. This implies that 

 the ancestral kiwis w^ere, like Megalapteryx, larger than the 

 hvmg birds ; and we may infer the same thing from the great 

 size of the egg. It is a legacy from a larger bird, which is not 

 easy to get rid of. The greater proportionate size of the female 

 is therefore probably due to its having to lay such a very large 

 egg. The males have decreased in size more rapidly than the 

 females, who were handicapped by such large eggs. I shall 

 subsequently show that the moas increased in size durino- 

 development, so that the usual rule of the male being larger 

 than the female would probably apply to them. But this 

 difference has not yet been proved ; and, if it existed, some 

 individuals of the larger sex must have been as small as, or 

 smaller than, some individuals of the smaller sex. 



Family DINOENITHIDiE. 



The slcull is remarkable for the great breadth and flatness 

 of the occipital region, and the broad and deep temporal fossae. 

 The plane of the foramen magnum is nearly vertical, and the 

 basi-occipital forms nearly a right angle with the basi-sphenoid. 

 There is a broad and deep depression between the condyle and 



* Trans. N.Z. Inst., vol. viii., p. 94. 

 t Trans. Zool. Soc, vol. xii., p. 172. 

 \ Phil. Trans., vol. clxxxii., p. 42, and pi. vi. 



