268 PEOFESSOE W. K. PAEKEE ON THE 



Example 45. Skull of Icterus vulgaris. Family Icteridae. Group Oscines. 



Habitat. South America. 



On the whole, this species agrees very closely with the last. In some things it differs ; 

 and, perhaps, being a younger specimen than the one studied, it is less ossified in its 

 nasal labyrinth, the floor of which (Plate XLIX. fig. 2, n. f) does not show the bony 

 centres seen in the last. The septum nasi (fig. 3, s. n, tr) is ossified ; it is largely alate ; 

 and its recurrent process is floored by a tongue of bone proceeding from the prse- 

 maxillary (ja.ma:). 



The vomer (u) has a wide head, in the horns of which a large septo-maxillary is 

 seen, just where it is grafted on the inturned lamina (s.tnx., i.a.l). The maxillo-pala- 

 tines [mx.]}) are not knives, but pouches; they have a narrow pedicle, which has a 

 pneumatic opening in it where it enlarges and bends ; a larger mouth is seen outside 

 the inflated end. 



This, as compared vnth the last, shows how variable a thing the pneumaticity of the 

 bones is, and that there must be considerable variation in the distribution of the 

 lesser air-cells. 



Example 46. Skull of Sturnella militaris. Family Icteridse. Group Oscines. 



Habitat. Ghili. 



My picture-gallery will be greatly enriched by a lateral view of the face of this 

 species, illustrating, as it does, the peculiarities of this type. 



The boss on the face-top (Plate XLIX. fig. 4, n.px), is seen dipping backwards to the 

 skull, and descending steeply to the beak-point. Laterally, the nasal, lacrymal, and lateral 

 ethmoidal mass (w, I, e.eth, p.])) are all seen to come flush with the face. Above, the 

 lacrymal forms a spongy subtriangular wedge jammed in between the descending crus 

 of the nasal and the ecto-ethmoid. Halfway down it becomes a narrow rod, suddenly 

 bent inwards ; it forms an arch, turning outwards below, and spreading its base over 

 the elegant egg-like os uncinatum (o. m), which almost reaches the zygoma {j). The 

 vomer (fig. 4, v, s.mx, and fig. 4 a, from above) corresponds very closely with that 

 of the last, but has a median process in its front emargination. The thick ossified 

 septum nasi (s. n) has three converging ridges, a fenestra in front, and a very large 

 notch below it and the mesethmoid. The alee and the alinasal and inferior turbinals 

 are soft. 



At the obtuse lateral facial angle the upper jaw is lifted at the side, like a dog's 

 lips in snarling, to make room for the crested mandible ; here the more median struc- 

 tures are seen, viz. the palatine, with its deep rib-edged transpalatine process, and the 

 palato-maxiUary bone nearer the outer margin (fig. 4, t.pa.p.mx). The pterygoids 

 and mesopterygoids are like what I have described in the fii-st species : here, however, 

 these parts are nearly ankylosed. 



