780 
ME. W. K. PARKER ON THE STRUCTURE AND 
The space between the “ posterior pterygoid processes ” (p.r.p.) and the basitemporals 
(b.t.) is filled with soft stroma, afterwards to be absorbed. 
In Plate LXXXIII. fig. 5, a lateral view of the nasal labyrinth, orbital septum, and 
palatine is given, which shows how loose . and membranous is the connexion between the 
ascending (orbital) plate of the palatine and the prefrontal or pars plana (p.p). The 
continuity of this anteorbital portion of the nasal labyrinth with the upper ethmoid 
(eth.), the aliseptal (al.s.), and with the alinasal ( al.n .) is clearly shown: these parts 
will be better understood by reference to the sectional views ; and by this means we 
shall also come to a fuller understanding of the rest of the skull at this stage. 
I shall describe the sections from before backwards ; and the first of these transversely 
vertical sections (Plate LXXXIII. fig. 6) passes through the middle of the prenasal rod : 
these sectional views are magnified from 8 to 16 diameters, and are given in Plates 
LXXXIII. & LXXXIV. 
A section through the fore part of the beak (Plate LXXXIII. fig. 6) passes through 
the broadest part of the prenasal cartilage, which is seen to be more convex above than 
below : it lies in the midst of a mass of fibrous stroma which is being rapidly converted 
into the solid part of the premaxillaries (p.x.) ; these are thickest above, have a cultrate 
edge laterally, and have, already, a small marrow cavity. 
A section made a little further back (fig. 7) shows the narrower cylindrical part of 
the prenasal rod, and passes through the tips of the trabecular horns, or fore part of 
the alse nasi (al.n.). Here the premaxillaries (p.x.) are composed of three parts — the 
nasal process (n.px.) above, the dentary margin (dpx.) laterally, and the palatine process 
(p.px.) on each side of the prenasal rod ; the section also shows the end of the maxillary 
(m.x.). 
The next section (fig. 8) has caught the fore part of the septum nasi, and has passed 
through the alinasal fold (al.n.), the lateral nasal wall ( l.n.w .), the nasal turbinal ( n.t.b ), 
the fore part of the maxillary (m.x.) and palatine (pa.), and the attenuated portions of 
the premaxillaries (n.px, dpx, p.px.). 
Fig. 9 shows the formation of the inferior turbinals (i.t.b.)-, the section is made where 
the lateral nasal wall is deficient, so that the aliseptal plate turns abruptly upwards 
and inwards to form the inferior turbinal scroll, which has exactly two turns. The 
nasals (n.) and nasal processes of the premaxillaries surmount the labyrinth ; and, 
leaving out other bony parts, I have shown the relation of the palatine plates of the 
maxillaries (maxillo-palatines, p.mx.) to the thick base of the the septum nasi. 
The 10th figure illustrates the structure of the ethmoid behind the anteorbital plates; 
the ethmoidal roof (al.e.) is seen to be concave at the mid line, and convex laterally, the 
perpendicular plate (p.e.) to be thinnest at the middle, and the basal part to have the 
same bulbous outline as the septum nasi. Here, surrounded by a web of fibrous tissue, 
is seen the crescentic section of the “rostrum” (r.b.s.), and on each side the shelving 
section of the palatines (pa.) at their broadest part. 
