156 ME. W. K. PAEKEK ON THE STEUCTUEE AND 



see that the crest is arrested at this low simple condition ; C. uniappendiculatus (op. cif. 

 pi. 74) is intermediate between C. hicarunculatus and C. galeatus [op. cit. pi. 71), in 

 which it attains its greatest actual height, although it retains the lanceolate outline. A 

 section of the broad upper ethmoid of the Mooruk-chick (Plate XIV. figs. 7 & 8) shows 

 that it is already one of the thickest bones in the skull ; anteriorly (fig. 7) its arch 

 is about one-third of a circle, further back (fig. 8) the arch is like that of a low-crowned 

 bridge, and all this wide, less elevated hinder part is a mere hollow dome, being 

 behind the supporting perpendicular plate, which, as a broad-topped wall, underprops 

 the foremost part of this ethmoidal crest (Plate XIV. fig. 'J,p.e.). Here one important 

 difference presents itself : in the other already described " Struthionidse," the upper 

 plate sends down a keel between the olfactory lobes, and it is this part which is pri- 

 marily thin, and always grooved for the lodgement of those organs ; in the Cassowary, 

 however, the vertical plate is completely formed by the middle or perpendicular eth- 

 moid, which is as much expanded at the top as the upper ethmoid in the other Ostriches. 

 The greatest fore-and-aft extent of the middle ethmoid (Plate XIV. fig. l,p.e.) at pre- 

 sent is 4 lines ; but it has reached the upper ethmoid above, and has reached within a 

 line of the basisphenoidal "rostrum" below. Between the lateral ethmoid (upper and 

 middle turbinals) the bone is thin (Plate XIV. fig. 7,p.e.); but it is not fenestrate as 

 in the Emu : this internasal " window" is very variable in the bird-class generally, 

 existing oftener amongst water-birds than amongst the arboreal tribes. The rest of 

 the cranio-facial axis is one continued, smooth, thickish, cartilaginous plate ; there being 

 no change as we pass from the vertical ethmoid to the septum nasi proper: this plate 

 (Plate X. fig. 19, s.n.) fills up the whole of the large intermaxillary angle (i. e. between 

 the body and its processes), as in the embryo of typical birds. 



As in the other " Struthionida;" and the Mammalia, there is a perfect continuity of all 

 the nasal cartilages ; the alse that grow from the upper edges of the great general orbi- 

 to-nasal septum being converted into cartilage by the metamorphosis of the whole of its 

 simple cells, without any of that breaking up into distinct territories which we see in 

 the purer bird-types. These upper olfactory wings extend on each side for a distance 

 of 1 inch 8 lines, the whole length of the skull and face being 2 inches and 8 lines ; 

 for the hinder end of the upper ethmoid lies in the same vertical line as the common 

 optic foramen, and the alee nasi fill up the angle of the intermaxillaries on each side 

 (Plate X. figs. 1 & 3). Posteriorly these long wings (connate in their bony stage) perform 

 the rare function of largely helping, dome-like, to roof in the hemispheres of the brain 

 (Plate X. fig. 20, & Plate XIV. figs. 1, 3, 4, & 8, eth.) ; in front they project somewhat 

 beyond the most jutting point of the nasal septum to form the breath-valves. All these 

 large birds, which "walk through dry places," have that part of the nose which is 

 merely supplied by the nasal portion of the fifth nerve, very large (largest of all in the 

 Cassowary), whilst the true olfactory region is small, and simple enough. The simple 

 fold of cartilage (Plate X. fig. 17, ale., u.t.b.), which, turning abruptly inward, forms a 

 triangular, somewhat swollen elevation outside the end of the olfactory bulb, is all we 



