DEVELOPMENT OF THE SKULL IN THE OSTRICH TEIBE. 171 



strengthened by the condition of the sternum in D. robustus. It is extremely probable 

 that at no far distant period New Zealand was inhabited by a large number of species 

 oi Dinornis, some of which may have had differences such as would, if we knew them, 

 enable us to make some subgenera out of this group. Perhaps, at present, Palapteryx 

 had better hold the smaller kinds, in a subgeneric way, and the largest kinds be called 

 Dinornis ; as for the so-called D. casuarimts, let it wheel off to its own phalanx, and 

 take rank as the chief of the Rails. 



Apteryx australis. 



Not possessing any materials for working out the development of the young Apteryx, 

 I must refer the reader to M. Blanchard's very valuable work, ' L'Organisation du 

 Regne Animal,' 20' Livraison, Oiseaux, Livraison 1". 



The two plates given in this first Number, on the Birds, are from drawings made by 

 M. Blanchard himself, of the osteology of a young individual of Apteryx australis ; 

 they are exquisitely drawn and engraved, and are of the highest interest and 

 value. 



As I am able to compare these plates with the large series of young struthious skulls 

 already described, and also with an almost indefinite number of growing skulls of the 

 more typical species of land- and water-birds (in some cases of very many stages of the 

 same species), I think that such a comparison will not be devoid of value. I must also 

 refer the reader to Professor Owen's invaluable contributions on this subject (see 

 Zool. Trans, vol. ii., and Osteol. Catalogue Mus. Coll. Surg. vol. i. p. 250. No. 1355*). 

 M. Blanchard's figure of the basal view of the skull (plate 2, fig. 2) does not give us 

 anything that is new, for in this region coalescence of the parts in this young individual 

 had already obliterated most of the sutures. The perfect struthiousness of the bird is, 

 however, well shown ; and the articulation of the large, distinct, flat posterior crura of 

 the vomer can be seen articulating with the splint-like anterior part of the pterygoid, 

 to the outer side of which bone the palatines have become anchylosed. The con- 

 verging ridges that meet at the root of the basisphenoidal " rostrum," one from each 

 basitemporal, join a keel which runs forwards under the rostrum, and backwards half- 

 way to the basioccipital. The " rostrum " is subcarinate in the round-headed Dromoeus 

 irroratus, so different from Struthio, Dinornis, and Rhea in this respect. On each side, 

 where the vomer becomes solid, the palatine can be seen articulating with the palatine 

 process of the long intermaxillary. The transverse occipital condyle, the continuous 

 head of the " os quadratum," and the very shallow drum-cavity, with its perforate roof 

 and thick obtuse exoccipital back-wall, are well shown in fig. 2. 



* There are some remarkable errors in this otherwise valuable abstract of Professor Owen's larger paper on 

 the Apteryx ; e. g. the " Ibis" referred to is not an Ibis at all, but one of the long -billed " Tringinae" (see also 

 p. 2-12. No. 1293); then the pterygoid processes in the Lacertine ;S(wr(a grow out of the basitemporals, and not 

 out of the basisphenoid, which is aborted in them ; lastly, the counterparts of the anterior pterygoid processes 

 of the " Struthionidse" exist in the embryo of all birds, and are developed in about two-fifths of the genera. 



2b2 



