DEVELOPMENT OF THE SKULL IN THE OSTEICH TRIBE. 161 



let into the frontal, is outside the broad turbinated nasal. Altogether the Cassowaries 

 have the smallest intermaxillaries, not excepting even the " Fissirostral " birds, e. g. 

 Caprimulgus, Cypselus, &c. The marginal grooves are well shown on the body of the 

 intermaxillary of the young Mooruk. They have their counterparts in the dentary rami 

 (Plate XIV. fig. l,p.x., d.). Beneath, the canal which contains the remnant of the 

 prenasal cartilage is Avell marked (Plate XIV. fig. 3, p-x.) ; behind that canal the bone 

 is double on each side ; the thick styloid dentary process running outside to the base of 

 the lacrymal, and the flat palatine process (mesiad) running back to the broadest part of 

 the vomer, and becoming notched towards the end. 



The prevomer (Plate XIV. p.v.) is well developed ; anteriorly it reaches further 

 forwards than the long vomer, and within 5 lines of the end of the upper bill; it is 

 1 inch 4 lines long, a line longer than the vomer. This middle intermaxillary splint 

 appears on the zygomatic margin of the cheek for 5 lines ; there is no maxillary to hide 

 it, but the jugal overlaps it for some distance. Externally, in front, a long styloid pro- 

 cess fits into that notch in the intermaxillary which should be the " anterior palatine 

 foramen;" behind this it widens inwards to join the broad part of the vomer (one of 

 its most essential and primary connexions), then for half an inch it is scarcely 1^ line 

 wide, and, notched behind, it gives off" a short spur to join the palatine, and a longer 

 one to fit to the jugal (Plate XIV. figs. 1 & 3, p.v.). 



The ascending process — that which gives the bone its thoroughly ophidian character 

 — is much like that of the Rhea (Plate XIV. fig. 1, p.v.) ; it is triangular, and curved 

 backwards at its blunt point : the point needed to be but a little sharper to have 

 made this process, with its broad basis, a very near counterpart, in form, of the prickle 

 (aculeus) of the gooseberry-bush. It is worthy of notice how the over-development 

 of the three almost equal intermaxillary splints has in these birds sufficed to wall-in 

 the soft nose-labyrinth in the absence of the great, usual, maxillary splint. This 

 latter bone is badly developed (above) in Snakes and Monitor-Lizards, and is a frail sieve 

 of bony openwork, strengthened above by a strong oblique beam from the intermaxil- 

 lary, in Hares and Rabbits (Lepus), creatures rich in oviparous characters. 



The vomer of the Mooruk (Plate X. figs. 18 & 19, & Plate XIV. fig. 3, v.) is of great 

 length, and is also very broad at the anterior part — that part which answers to the 

 lower portion of the bone in the Chelonian ; it is very much split at both ends, espe- 

 cially behind, and, as may be seen also in the adult common Cassowary, the bone is like 

 two pieces conjoined by a long isthmus in the middle. 



Anteriorly the vomer underlies the septum nasi, then two-thirds of the rostrum of 

 the basisphenoid (Plate XIV. fig. 7, r.b.s., v.); and its hinder lobes are strongly 

 fitted beneath each " mesopterygoid " spur of the pterygoids (Plate XIV. fig. 3, v. pg.). 

 So that Nature has very carefully builded the bird's skull, laying balk upon balk; 

 first the rafters (trabeculae) grew together, and made the strong beam-like basis of the 

 orbito-nasal partition-wall ; then the pituitary ffoor grew forwards, first as cartilage and 

 then as a bony rostrum beneath this beam, fitting in a groove-and-tongue manner most 



MDCCCLXVI. 2 A 



