DEVELOPMENT OP THE SKULL IN THE OSTEICH TEIBE. 169 



Psophia agrees with this huge bird in another point in which the latter diverges from 

 the ordinary Rails, viz. in the perfectness of the interorbital septum. 



Professor Owen [op. cit. p. 351) was somewhat staggered at finding the sulcus where 

 the coronal suture had been in the Great Rail's skull, " behind the relative position 

 of the persistent coronal suture in the skull of the Palapteryx." A very early stage 

 of the Gallinule's skull explains this ; for this and many other water-birds have the 

 parietals very narrow, and the frontals extending far back ; whereas the " Struthionidse," 

 one and all, including the Apteryx, have large broad parietals. The author of the paper 

 quoted above seems to have despaired of finding any near relative for his supposed 

 Dinornis casuarinus (see p. 375). I think that its relationships are evident enough, 

 but its " spot is not the spot of the" daughters of the Ostrich. 



Yet the predicament in which this huge bird seemed to be placed is really that of 

 the Psophia ; for at present we know of no near relative to this bird, which having a 

 truly ralline head set upon the body of a Crane, yet possesses also the superorbital chain 

 of ossicles in common with the struthious Tinamou ; this character being borrowed from 

 the Skink-lizards, who borrowed it from the ganoid Fish. Then, curious enough, the 

 Psophia, as we have seen, differs from the Tinamous, the Cranes, and the Rails in having 

 a strongly decurved beak and a perfectly ossified interorbital septum — in this agreeing 

 with the most extraordinary development of the ralline type. Does all this bear upon 

 the morphology of the struthious skull ] Certainly ; for I have to eliminate the false 

 Dinornis., and to put the true typical bird beside the aberrant Ostrich, for comparison's 

 sake : the gigantic Notornis served well for such a comparison. The author of the oft- 

 quoted paper (p. 373) speaks of its "crocodilian cranium;" this may lead to some mis- 

 conception. This is merely in the thickness of the basal part of the skull ; and that is 

 basilateral, and not mesial, as in the Crocodile. 



But in the presence of the large basitemporal pterygoid processes, it agrees with the 

 rest of the Rails and the Psophia, and only differs from them in their relative size; 

 and the basal region is relatively quite as thick in Fulica and Crex. Then the extra- 

 ordinary development of the tympanic cavities and of the Eustachian tubes in the 

 Crocodile is not in anywise repeated in the Great Notornis, which only differs from the 

 Ostriches, and not from typical birds. There are birds certainly which come near the 

 Crocodile in the upward extension of the tympanic cavities, e. g. the Albatros and the 

 " Rapaces," especially the Owls ; in these the large diverticula, which pass upwards and 

 inwards, do virtually meet at the mid line through the openness of the diploe which 

 intervenes (at top) between the actual cavities. These extensions upward of the tympanic 

 cavities can be seen distinctly in the " Rallinse," and a trace can be detected in the 

 Ostrich ; but in no known bird is there anything like the Eustachian meatuses of the 

 Crocodile ; we might as well look for such pterygoids and such a palatine region as this 

 creature possesses. 



There is nothing more characteristic of the struthious bird than the structure of its 

 intermaxillaries and nasals; and the only birds which approach the Ostriches in the 



MDCCCLXVI. 2 B 



