THE QUADRATE BONE IN BIRDS. 3 
mass of bone above the inner aspect of the anterior mandibular condyle; the ridge 
. before-mentioned is visible passing down to it from the region of the capitula. 
The mandibular articulation is peculiar ; the posterior portion is disproportionately 
small, and its inner and outer regions are not clearly separated by a groove; the 
bulky anterior part (a.a.) is bevelled off on its outer side into an accessory trochlear 
surface (17.t.). 
No other quadrate that we have studied approaches this in character. 
DrsmMocNATHA : 1.—CHENOMORPH. 
“Ri 
Sor 
. 
Fig. 3. ANSER DOMESTICUS. 
In the Common Goose, the two capitula are only slightly separate; below and 
to the outer side of the external capitulum is a concave surface, passing below into 
a small accessory head (h'). The anterior process is short and pointed, somewhat 
roughly fashioned on its outer, more concave and delicate on its inner, aspect. The 
pterygoid condyle and the quadrato-jugal cup are both imperfect—the former, indeed, 
is quite rudimentary. The mandibular articulation is peculiar; it possesses only — 
the outer moiety of its posterior part, which unites with the (normal) anterior 
condyle to form an obliquely-placed trochlear articulation. When seen from below, 
a considerable overhanging stretch of bone is visible posterior to this articular 
surface. The peculiar form of the joint-surface is connected with the fact that 
“the angle of the mandible is strongly produced and upcurved,” as in the 
gallinaceous birds. The latter feature and the rudimentary inner lamina of 
the palatine bone were noted by Huxtey as features in the skull recalling the 
Alectoromorphe. A study of the quadrate emphasises the resemblance. The 
quadrate of the Goose differs very greatly from that of any other Desmognath 
that we have examined. 
T].—AMPHIMORPH 2. 
