THE SKULL IN THE WOODPECKERS AND WRYNECKS. 19 



begin above ; the one in front of this is the inturned and flattened fold which represents 

 the upper turbinal (u. tb). Here the inferior turbinal (i. tb) sends out an inner out- 

 growth like the one in front of it. 



The middle turbinal is a mere ridge in the front of the pars plana, where the inferior 

 turbinal ends (see in Oecinus, Plate V. fig. 2, m. tb). When the razor has cut through 

 the thickest part of the rapidly ossifying " mesoethmoid," we get a view of the orbital face 

 of each "pars plana" (Plate IV. fig. 10, pe,pp) with its conjugational angle corresponding 

 to the " os uncinatum." It is in this section that we get a view of the " median sphenoidal 

 sinus " (m.sph) and the two vomers ; (see enlarged view, fig. 11) in this region ; both 

 endostosis and ectostosis are at work, hardening the " perpendicular plate," which grows 

 outward into the " ali-ethmoids," which, infolding themselves and becoming pinched 

 at the fold, give us ultimately the ear-shaped wavy crenate upper turbinal (compare fig. 9, 

 with Plate V. fig. 2, u. tb). 



Already I find a small styloid lacrymal behind the nasal crus, and a distinct centre in 

 the orbito-sphenoidal region. 



Summary of characters of the " Saurognathous " type of Palate. 



A. Trabecular Arch. 



1. Retention and ossification of trabecular cornua, and of basitrabecular (prsenasal) 



rostrum. 



2. Addition thereto, in certain types, of a pair of " labial " cartilages, which do not 



form the foundation of an oxhead-shaped compound vomer as in the Passerinse. 



3. Detachment, in Gecimis, at least, of part of the nasal wall, after the ingrafting on 



it of a septo-maxillary. 



4. Great number and bilateral independence of the vomerine series of bones, some 



of which are azygous. 



B. Palatine Arch. 



1. Absence of a distinct mesopterygoid, the process answering thereto being very 



long, and in the embyo reaching the vomer of that side, as in the New- 

 Zealand Lizard Hatteria. 



2. A dagger-shaped basipalatine between the right and left bones. 



3. Absence of a distinct " transpalatine." 



4. Presence of a postpalatine bone in the most generalized form (namely, Picumnus). 



5. Absence of epipterygoid hook, and presence of a large spur for muscular attach- 



ment on the pterygoid. 



6. Abortive development of maxillo-palatine plates, and presence of a distinct palato- 



maxillary bone on the left side only. 



C. Hyoidean Arch. 



1. Abortive development and early fusion of the ceratohyals. 



2. Double " infrastapedial " and ossified stylohyal. 



1)2 



