172 ME. W. K. PAEKEE ON THE STEUCTUEE AND 



The lateral view (fig. 3) shows that the frontal had not coalesced with the parietal 

 above, nor with the alisphenoid below ; and also its distinctness from the nasal and 

 antorbito-lacrymal mass anteriorly. 



The gentle manner in which the occipital region graduates into the parietal is well 

 shown in this figure (3), reminding the observer of the skulls of the Echidna, Mole, 

 and Shrew ; we also see the similar graduation of the skull into the face. The squa- 

 mosal has united with the lower edge of the parietal ; it binds the os quadratum 

 strongly, with its large descending process, as in the other " Struthionidse." The ante- 

 rior sphenoid is of small extent, the " rostrum " is distinct from its base, but both base 

 and alae are completely confluent with the largely developed lateral ethmoids. These 

 plates are very large and swollen ; the upper, answering to the cribriform plate and back 

 of the upper turbinal, the lower part to the pars plana, or back of the middle turbinal. 

 There is a large notch in the lower edge of the orbital plate of the frontal ; but this is 

 made into a large irregular foramen by the immediate contiguity of the upper edge of 

 the simple cribriform plate; this is the " upper orbital fontanelle;" and at this part the 

 olfactory crus is only protected externally by membrane. There is no such open space 

 in the skull of the adult African Ostrich, and in the Ehea it is only large enough to 

 allow the olfactory crus to escape into the orbit, along which it passes to gain the now- 

 cribriform chink between the vertical ethmoid and its ala. In the Tinamou (Tinamus 

 robustus and variegatus) the broad end of this fontanelle and the olfactory chink are 

 half an inch apart at the top of the large orbit. The postfrontal part of the alisphe- 

 noid is not developed, and the feeble postorbital process of the frontal does not come 

 near that part of the skull ; this is similar to what is seen in the Mole. The tumid 

 "pars plana" projects outwards to anchylose with the inner edge of the lacrymal, which 

 has the usual fenestra, but is very small, and is shorn of its superorbital part ; more- 

 over the large lateral development of the ethmoid has pushed up against the descending 

 crus of the nasal, another unique character for a bird. 



The middle plate of the ethmoid is not diflierentiated from the septum nasi, which has 

 a fenestra behind, between the fullest part of the inferior turbinals. The metaptery- 

 goid process of the os quadratum is seen to be obtusely conical, as in the Emu, the 

 quadrato-jugal to be much longer than is usual in the " Struthionidae," the malar to be 

 of the ordinary size, and the zygomatic process of the prevomer to reach nearly half- 

 way along the zygoma. 



With the skulls of two species of Tinamou before me, I am able to decipher the 

 structure of the nasal of the Apteryx ; for, as in those birds, it has a descending bar to 

 this bone, which, as in them, thickens as it descends obliquely forwards, and is pedate 

 below ; behind, and within it, there is evidently a slight upgrowth of the prevomer (the 

 ophidian process), such as I shall soon describe in the Tinamou. 



The end view of the Apteryx's skull (pi. 2. fig. 3) shows the roundness of the crown, 

 the great width of the occiput (unique in being the widest part of the skull), the trans- 

 verse character (not hemispherical) of the occipital condyle, the projection, so smooth 



