262 PEOFESSOE W. K. PAEKEE ON THE 



In Sericornis the pterygoids (fig. 5, 2^9) a^re slender and arcuate, and the epiptery- 

 goid is short and broad {e.pg), 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 {i.pa) is aborted ; the ethmo-palatine is of moderate size, and the 

 transpalatine {t.pa) broad and foliaceous ; the whole prsepalatine bar (pr.pa) is long and 

 slender. The palatal processes of the pi-semaxillary are suppressed or absorbed ; the 

 palato-maxillaries do not appear ; and the maxillary (mx) is quite ankylosed to the ros- 

 trum and to the jugum (J). The pedicle of the maxillo-palatine process (mx.p) curves 

 backwards, and not forwards as in Ptilotis (figs. 3 & 4, mx.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 vomerine moieties, 

 as in Petroica (Part I. plate Ix. 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 {re. 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 {tr, s. w). The nasal wall contracts and 

 grows inwards, behind, to form the inturned ala {i. al), 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. tb). 



The lateral ethmoids (e.eth, p.p) are like those of Ptilotis : they are one mass of 

 spongy bone ; to the fore face of this mass the inferior turbinals («. tb) are attached. 



Example 37. Skull of Sittella, sp. % Family Paridse. Section Tracheophonse. 



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 diafted ofi" 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 ^. 



The description just given of the skuU of Sericornis may serve for this also, save that 

 it may be noticed that the transpalatines {t.pa) have a larger and less-notched leafy ex- 

 pansion, the interpalatine spurs {i.pa) are well developed, and the maxillo-palatine 



' I must confess that I cannot account for the fact that Pratincola ruhetra has the same type of skull (palate 

 especially). A thorough examination and comparison of these Australian types with the Chats generally is 

 very desirable. 



