PEOF. W. K. PARKER ON iEGITHOGNATHOUS BIRDS. 301 



rostrum (pn), meeting beneath the axial parts ; they are continuous with each other 

 also ; and this compound structure is one very important to be understood : morpho- 

 logically the " recurrent trabecular cartilage " (rc.c) is formed by the free ends of the 

 comua trabeculse. 



The space between the front wings and their outer wall (al. n) is the external nostril 

 (e. n). The outer wall of this nasal vestibule has in its inner side the large " alinasal 

 turbinal " {a. tl) ; and this is separated by a narrow space from the subnasal (trabecular) 

 laminae {tr). 



Behind, both wall and turbinal are continuous with the bony vomer {v). All this is 

 made clear by the transverse sections. 



The first of these (fig. 2) was made close behind the external nostril : the lateral 

 and upper portions are here continuous. The razor has passed through the thick part 

 of the nasal process of the prsemaxillaries [n:px), the upper crus of the nasal (;t), the 

 dentary part of the prsemaxillaries {d.])x), the maxillary before it has given off the 

 maxillo-palatine process (mx.p) and the prsepalatine spur {pr.pa). Below, the nasal 

 wall (h. w) rests in a groove of the maxillary ; at its middle it gives off' the " alinasal 

 turbinal " {a. tb), which is large, and is thrice bent upon itself in an angular manner, 

 giving off" at the last two bends a slight secondary outgrowth. Above, the " alinasal " 

 passes into the " aliseptal " cartilage (cd.s, fig. 3) ; and here we have a section of the 

 fore end of its turbinal, the " inferior " — anterior in the Bii-d, although below the others 

 in Man. This is here scarcely more than half a cylinder. In this region the common 

 wall between the nasal sacs is continuous with the crests growing from the flat, tilted, 

 and coalesced " trabeculee ;" these are seen to be large and curved. 



The next section (fig. 3) is through the maxillo-palatine processes (mx.p), which here 

 are distinct in section from the marginal portion (mx) ; they form a pair of slanting 

 planks, on which the compound vomer rests at its sides. The roof-bones (n, n.px) are 

 here flattened out over the broad gently swelling " aliseptal " roof. At this point the 

 wall has died out below ; and the aliseptal lamina, after growing downwards and inwards 

 for a short distance, folds itselt suddenly inwards, and is coiled two and a half times 

 {i. tb). Between these large inferior turbinals a diff'erentiating cleft has appeared, 

 causing a dehiscence of the nasal septum (s. n) from the trabecular bar and 

 crest [tr). The cartilages which lean towards this on each side are the common end 

 of the alinasal wall and its turbinal ; and the bony plate which is grafted upon both and 

 binds them together is the vomer [v). The anterior face of the same somewhat solid 

 section (fig. 4) shows more of the nasal cartilage ; it is magnified twice as much. 



The part of the trabecular commissure and crest {tr) seen here shows it to be small ; 

 it is not, however, far from the "hinge;" the trough formed by the vomer and the 

 " inturned alinasal laminae" [i. a. I) is very deep and large; and in the adult the bony 

 matter, creeping along the cartilage to some distance, gives the vomer, in the macerated 

 skull, the appearance of one very deeply scooped bone. 



