274 PROFESSOR W. K. PARKER ON THE 
by their maxillo-palatine process. This region of the maxillary, which in Mammalia 
and Crocodiles forms so much of the great “ hard palate,” in the Grosbeak is the frailest 
of all bony structures (figs. 1 & 2, ma.p): their wse in this bird is to contain a most 
minute globule of air from the naso-palatal labyrinth. Arising from the supero-internal 
face of the bone as a fine arcuate filament, they gradually widen ; and in widening they 
become scooped below. ‘They then become bowed backwards as well as inwards, nearly 
meet below the vomer, and have two fifths of their scooped part closed in so as to form 
a microscopic fest-tube, which, however, is irregular in form and flattened from above 
downwards. 
The vomer is Passerine in the highest degree (figs. 1, 2, v). It is ox-faced in shape ; 
and the horns and ears are represented by processes of bone that have trespassed upon 
the nasal wall; the forehead also is seen on the lower face, in front—a triangular 
thickening ending behind in a keel, and in front forming the sinuous margin of the 
bone. The vomer is deeply grooved above, and lost in the palatine commissure 
behind. 
A considerable amount of ossification has occurred in the nasal labyrinth—in the 
septum most of all, which is sharply segmented off from the mesethmoid, is sharp below, 
behind ; but its alate part has ankylosed with the rostrum, and runs invisibly into the 
proximal ossified part of the al nasi. Both alinasal and inferior turbinals are three 
fourths bony. The great ethmoidal mass projects above in the same degree as in the 
Buntings. So also the spongy pars plana (p.p) is scooped towards the eye, and has a 
round notch on its outer margin; but here its “foot” is unusually prolonged, as in 
those Psittacidee whose suborbital bar is imperfect. In these types, such as Pse- 
photis multicolor, it is easily seen that a large os uncinatum has coalesced with the 
pars plana; so it is in Coccothraustes (fig. 1, 0.u, p.p); for, although ankylosis has 
taken place, the remains of the suture can be traced. 
Example 52. Skull of an Averdavat (Estrelda astrild). Family Ploceide. 
Group Oscines. 
Habitat. South Africa. 
Intensity of ossification, with equivalent ankylosis of independent parts, takes place in 
this, one of the smallest of the Finches, equally with the Grosbeak, one of the largest. 
My study of these small southern forms has been in the type given above, in the 
Crimson Finch (Estrelda phaéton) from Port Essington (Australia), and in the young (as 
Mr. Sharpe believes) of Habropyga subflava. In these types the broad strong rostrum 
is deflected as much as in the Buntings and the Corn-Buntings, and has a high back 
near the frontal region. For their size the skull is nearly as strong as in the Grosbeak ; 
but they lack the rimmed orbit. 
The pterygoids are similar, and have a good epipterygoid hook (Plate L. figs. 4 & 5, 
e.pg, pg); but in these forms the spatulate end ankyloses with the palatine. In the 
