DEVELOPMENT OF THE SKIJLL IN THE OSTEICH TRIBE. 159 



The broadly triangular, deeply lancinate (or rather runcinate) tongue has in its sub- 

 stance the lower part of the second pair of poststomal rays ; these are coalesced at the 

 mid line, and together are like a thick heart-shaped leaf (Plate XIV. fig. 12, c.h.). 

 The basal cartilage [l.h.), thick in the middle and bluntly pointed at both ends, fits in 

 front into the notch made by the posterior divergence of the flat " comua minora." 

 The lower thyro-hyal {th. 1) is considerably ossified, the upper piece {th. 2), the cerato- 

 hyals, and the combined basi- and uro-hyals {bh., uh.) not at all; the whole structure 

 agrees closely with the like parts in the Emu. 



There is nothing especial in the auditory " columella" (Plate XIV. fig. 2, sf.), which 

 agrees with that of the Emu. 



There is very much that is of interest in the splint-system of bones in the Mooruk's 

 skull. There is very little trace of the posterior fontanelle (Plate XIV. fig. 4), for 

 the superoccipital has already fitted into the very obtuse angle formed by the meeting 

 of the parietals behind ; the anterior fontanelle {fo.) is lozenge-shaped, and is 2 lines 

 across. The squarish parietals {p.) are becoming thick, and are already considerably 

 scooped to form the temporal fossae ; they are very curved, for the skull is high, as in 

 the Emu. The frontals are still higher, are becoming thick, but are very squamous 

 behind; at the mid line (Plate XIV. figs. 1-8, /".) they are cut ofi" from much of their 

 territory by the uprising of the overgrown ethmoid ; so they are mere styles in front 

 and lie under the edge of the broad ethmoid, and wedge themselves in between and 

 below the lacrymals and nasals (Plate XIV. fig. 7). The orbital plate of the frontal is 

 for the most part only 2 lines in breadth, but it is sending a long pointed lamella to be 

 strapped to the side of its proper primordial pattern — the orbito-sphenoid (Plate XIV. 

 figs. 1 8l 14,/., OS.). The lacrymals {I.) — the splints that apply themselves with exceed- 

 ing closeness to the lateral ethmoidal region (Plate X. fig. 19, & Plate XIV. fig. 7) — 

 are very large, as in most of the Ostrich-group ; they send a long process to supply the 

 place of the absent superorbitals ; and apply themselves by a very long harmony-suture to 

 the still larger nasals ; the antorbital plate of the lacrymal is thicker than usual, has no 

 fenestra, and is somewhat pedate below (Plate X. fig. 18, «& Plate XIV. fig. 7). The 

 nasals are very peculiar, if compared with those of the purer types of birds ; they come 

 nearest those of the Rhea as to their mutual approach at the mid line, and to those of 

 the Great Ostrich in the size of the very ornithic descending process (Plate XIV. figs. 

 1 & 3, n.). Yet this process is very feeble ; and on the whole the nasals of the Casso- 

 wary are an exaggeration of what is seen in the other " Struthionidse," even in those 

 very characters which are especially struthious. Behind, they reach to the very middle 

 of the superorbital region, are there mere thick styles widely thrust apart, like the half- 

 open blades of a pair of scissors ; but they become very broad and massive between the 

 body of the lacrymals, and where they have met in front of the narrow end of the 

 exposed upper ethmoid. Even in this young specimen the nasals lie together for one- 

 third of an inch, and then, for the same distance, gently diverge to let in the feeble, 

 coalesced nasal part of the intermaxillaries (Plate XIV. %. 3). The descending cms of 



