136 Zoological Society: — 



head, the well-roofed eyebrows, the perfectly bony orbit, and a man- 

 dible such as the eye searches for in vain elsewhere — all these are 

 outstanding characters in the highest type of Parrots, and, above all, 

 in the genus Microglossa. 



The huge, mobile face is but one bone in the adult, and yet it is 

 composed of a great variety of parts that have become blended into 

 one thick mass, perfectly void of sutures. The nasals, intermaxil- 

 laries, prevomers (the vomer is not developed in the Psittacida;), the 

 nasal septum, the inferior turbinals, and the alse nasi, all these go 

 to form this large compound bone. There are, therefore, six splint 

 bones ; and the axial bones are four for the septum, two (at least) 

 for the inferior turbinals, and two for the alse nasi, thus making 

 eight more, or fourteen bones in all. The highly complex skull 

 also is completely fused into one bone, and it has in it the separate 

 parts that form the auditory and olfactory sense-capsules. But the 

 original attachment of the pieces of the arrested palato-pterygoid 

 arch is loosened so as to let the ascending (proximal or orbital) pro- 

 cess of the palatine lie half an inch below its proper foundation, viz. 

 the pars plana or antorbital. Anteriorly, the palatine is thick and 

 transversely expanded, and its convex elliptical end fits in a glenoid 

 cavity in the end of the prevomer of the same side. Further back, 

 at its proximal plate, it is two- thirds of an inch high, it scarcely 

 becomes less than half an inch ; and its emarginate hinder end reaches 

 to behind the " membrana tympani," full a quarter of an inch be- 

 hind the somewhat slender rod-like pterygoids. The latter bones, 

 although an inch in length, are thus completely overlapped by the 

 palatines. The small, late-appearing mesopterygoids have early coa- 

 lesced with each other, and they have united also with the front corner 

 of the basicranial edge of the left palatine. The malar bone articu- 

 lates, like its axis, the palatine, with the prevomer. The epiptery- 

 goid process of the pterygoid is obsolete ; the metapterygoid pro- 

 cess of the quadrate bone is small, conical, and anteriorly placed, as 

 in its autogenous counterpart in the non-venomous Serpents. The 

 hinge-convexity of the quadrate bone is semicircular ; the cupped 

 process for the jugal is large and projecting ; and a well-developed, 

 outstanding, oval condyle is received by the cup at the end of the 

 pterygoid. The heads of the os quadratum — answering to the crura of 

 our anvil-bone ("incus") — are well developed, but do not stand as in 

 other birds ; for that which is related to the sympletic cartilage of 

 the stapes is directly inside the outer or prootic head. In birds 

 generally, this incus-head projects far backwards, overlapping the 

 opisthotic, and overshadowing the auditory " fenestras," to articu- 

 late with the exoccipital. The splints of the lower jaw, ten in 

 number, have all become one piece, as unlike as possible to the 

 simple Meckelian rod on which they were modelled. The sym- 

 physis is an inch in extent, and the bone is transversely flattened 

 below, so as to be an inch wide at what should be the intermandi- 

 bular angle ; this is, there, a gently concave transverse margin 

 having a rounded edge. The greatest height of the mandible is 

 1| inch; the angular process passes further back than the exocci- 



