262 PROFESSOR W. K. PARKER ON THE 
In Sericornis the pterygoids (fig. 5, pg) are slender and arcuate, and the epiptery- 
goid is short and broad (e.pq), whilst the palatine end is much dilated ; it is separate 
from its own lanceolate segment, the mesopterygoid, now completely united to the 
postpalatine (pt.pa). The keels of the latter part are moderately developed; and the 
interpalatine spur (¢.pa) is aborted; the ethmo-palatine is of moderate size, and the 
transpalatine (¢.pa) broad and foliaceous ; the whole prepalatine bar (pr.pa) is long and 
slender. The palatal processes of the premaxillary are suppressed or absorbed; the 
palato-maxillaries do not appear; and the maxillary (mz) is quite ankylosed to the ros- 
trum and to the jugum (j). The pedicle of the maxillo-palatine process (m.p) curves 
backwards, and not forwards as in Ptilotis (figs. 3 & 4, ma.p); and the dilated end is 
pedate, with an anterior “keel,” as in Acanthorhynchus (fig. 1). The vomer has its 
margins evidently composed of splints distinct from the two main yomerine moieties, 
as in Petroica (Part I. plate lx. figs. 9 & 10, v) and the types next to be described. The 
nasal capsule is not hard; and yet it is in some degree calcified, retaining its form 
well in the dry skull; it is very elegant and instructive in this lower view. 
In front, the trabecular cornua have coalesced to form a triangular carinate recurrent 
cartilage (7c. c); behind this part the subseptal region of the trabecular bars had 
become foliaceous, the leafy flaps being sinuous; the hinder third of the bar forms 
merely a thickened selvage to the septum nasi (fr, s. 2). The nasal wall contracts and 
grows inwards, behind, to form the inturned ala (7. a/), on which the vomerine bones 
are grafted. The floor of the labyrinth is imperfect below, and especially in front, 
showing the large alinasal turbinals (a. ¢0). 
The lateral ethmoids (¢.eth, p.p) are like those of P#ilotis: they are one mass of 
spongy bone; to the fore face of this mass the inferior turbinals (7. 4b) are attached. 
Example 37. Skull of Sittella, sp.? Family Paride. Section Tracheophone. 
Habitat. Australia. 
In its skull (fig. 6) this form agrees with Sericornis more closely than it does with 
Sitta (Plate LI.). Its osteological characters are also like those of Petroica; and 
these small Australian Passerines, however much their other characters may demand 
that they be drafted off into various families, yet to the morphologist appear as one 
very natural group, having so much in common as to support the doctrine of unity 
of origin 1. 
The description just given of the skull of Sericornis may serve for this also, save that 
it may be noticed that the transpalatines (¢.pa) have a larger and less-notched leafy ex- 
pansion, the interpalatine spurs (7.pa) are well developed, and the maxillo-palatine 
1 T must confess that I cannot account for the fact that Pratincola rubetra has the same type of skull (palate 
especially). A thorough examination and comparison of these Australian types with the Chats generally is 
very desirable, 
