ON. THE ANATOMY OF CHAUNA DERBIANA. 327 ‘ 
into the nature of the lamellirostral type. Prof. Parker tells us that 
“the great embryological distinctions between the skull and face of 
the Geese and Fowls are, first, that in the latter the space between 
the periotic mass and the superoccipital cartilage is a mere chink, in 
the former a persistent oval space; and secondly, that the anterior 
parts of the face, viz. the premaxille, prevomers~[maxille], and 
dentaries are small and compressed in the Fowls, large and outspread 
in the sifting birds.” A glance -at the accompanying figures of the 
posterior surface of the skulls of a Magellanic Goose, a Derbian 
Screamer, and a Razor-billed Curassow will enable the reader to 
decide for himself which of the two groups, the Anseres or the Galline, 
the Screamer more closely approaches. It evidently does not share Page 197. 
the peculiarities of the former, in all species of which the surface of 
origin for the pair of large extensor muscles of the mandible is cha- 
racteristically compressed from side to side, and elongated from above 
downwards, at the same time that there is the pair of openings above 
the foramen magnum (figs. 1, 2, 3, p. 328). 
Again, from a comparison of the inferior surfaces of the same three 
skulls, it is equally evident that in the Screamer the premaxille, 
maxillaries, and dentaries agree with the same bones in the Gallina- 
ceous bird in not being large and outspreading. The palate of Chauna 
is represented in fig. 4. 
In the Screamers the skull is, no doubt, as in the Anseres, desmo- 
gnathous, having the maxillo-palatines united across the middle line; 
but this character is not sufficiently important to compel us to unite 
the two groups; for if such were the case it would be necessary to 
give credence to an association of birds which is in other respects 
extremely unnatural. In the Capitonide, for instance, Megalema is 
not desmognathous, whilst Tetragonops is so. 
As before stated, in the Anserine birds the lachrymal region is 
specially long. This is least marked in the Cereopsis Goose (Cereopsis 
nove-hollandie), where, however, it is clearly apparent. In Chauna, 
the lachrymal region is as short as in the Gallinw, not in the least- 
elongated. 
In both the Anseres and Galline the pterygoid bones have large 
faceted surfaces for articulation with the basisphenoid rostrum. In 
both groups these facets are situated very far forwards—quite at the 
anterior ends of the bones in the latter; in Chawna, however, these 
articulations are quite independent of the anterior ends of the bones 
(fig. 4), being nearly as far backward as the middle of their otherwise 
free moieties. 
As to the quadrate bones, their cranial articulations are bifid, 
which is the case in all birds except Struthio, Rhea, Dromeus, 
Casuarius, Apterye, the Crypturi, and some (most) of the Galline. 
a 
