24 The Systematic Position of Zeledonia coronata. 



EXPLANATION OF THE PLATES. 

 Plate I. 

 Zeledonia coronata, p. 1. 



Plate II. 

 Figs, l-o shew the various forms of the tympanic cavity from the right 



side for comparison with that of Zeledonia, seen in the side view 



of the skull of fig. 9. 

 Fig. 1 . The tympanic cavity of Merula. X 2. Here the lateral occipital 



wing (l.o.io.) is much inflated to form a large chamber in front of 



the tympanic membrane. This wing, it will be noticed, curves 



upwards and forwards to terminate on the zygomatic process. 



This is an extremely specialized type. 

 Fig. 2. The simpler form of the tympanic cavity in Geocichla, intermediate 



in type between that of Turdus and Sialia. x 2. 

 Fig. 3. The tympanic cavity of Sialia. representing probably the simplest 



type among the Turdidae. x2. Letters as before. 

 Fig. 4. The tympanic cavity of Daulias luscinia. x2. A specialized 



type, inasmuch as the lateral occipital wing (l.u.io.) is continued 



upwards to the base of the postorbital process (p.o.p.). 

 Fig. ■">. The tympanic cavity of Menura superba. Nat. size. The 



tympanic cavity as seen here is possibly of a more primitive 



character than in any of the Turdidaa. 

 Fig. 6. Palate view of the skull of Geocichla, shewing vestigial basi- 



pterygoid processes (bp.p.). x 3. 

 Fig. 7. Palate view of skull of Zeledonia coronata. x2. 

 Fig. 8. Palate view of skull of Sialia ivilsoni, to compare with that of 



Zeledonia. x2. Note the larger and inflated maxillo-palatine 



processes (mx.p.). 

 Fiff. 9, Lateral view of skull of Zeledonia coronata. X 2. Note the 



position of the zygomatic process (z.ps.). 

 Fig. 10. Hemipterygoid of Menura superba. This does not appear to 



fuse with the palatine till comparatively late, in life, x 2. 

 Fig. 11. Rhamphotheca of Zeledonia coronata, to shew the remarkable 



operculum (op.). x2. 

 Fig. 12. Hemipterygoid region of skull of Turdus, to compare with that 



of Menura and Zeledonia. x2. 



Explanation of the Lettering. 



pa. = palatine. 

 jit. = pterygoid. 

 p.o.p. =postorbital process. 



«.jo. = antorbital process. 



a.£i. = alinasal turbinal. 

 &/)./?.= basipterygoid process. 



/i.pf.=hemipterygoid. q. = quadrate. 



l.o.w.= lateral occipital wing. vo. = vomer. 



mx.p. = maxillo-palatine process. z.p.s. = processus zygomaticus 



op. = operculum. squamosi. 



o.«.=otic articular surface for z.s. = squamosal articular surface 



quadrate. for quadrate. 



