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Show 268 MR. W. P. PYCRAFT OX THE [Mar. 17, In the Musophagi the angular is sharply truncated posteriorly, and the internal angular process is short and blunt. In Schizorhis the ramal vacuity is closed posteriorly, in Turacus it is closed conq^letely, by the coronoid. The Hyoid. Unfortunately the hyoid bones have been preserved only in one or two of the skeletons of this group in the Museum Collection. Years ago, when these skeletons were made, according to the prevailing custom, the hyoid bones were not regarded as of value. In Scythrops the basihyal is slender and rod-shaped ; the 1st basibranchial triangular, with concave sides, the 2nd of medium length, styliform and tapering. The ceratobranchial and epi-branchial are subequal in length and offer no points for special comment. In the Musophagi the basihyal bones are reduced to mere vestiges. The 1st and 2nd basibrancliials are short and fused. The ceratobranchials are only slightly longer than the epi-branchials. iii. T he S k u l l of th e N e s t l in g . The National Collection of nestling skulls of this group is extremely limited, containing only one skull of Cuculus canorus and one of Geococcyx californianus. A series of skulls of nestlings and of immature individuals of various species of Cuckoos, as well as of Plantain-eaters, would be a useful addition to the Collection. At present the latter contains no skeletons of nestling Plantain-eaters and few skeletons of adults. a. Cartilage-bones. The basioccipital is somewhat linguiform in shape, and widens gradually from behind forwards. It is bounded on either side by the lateral occipitals, in front by the basitemporal plate. Its posterior border forms the greater portion of the occipital condyle. The exoccipital, or lateral occipital, viewed externally, takes the form of a broad horizontal plate bounding the basioccipital on either side, and extending backwards and outwards, expands into a fan-shaped plate, the superior half of which is wedged in between the supraoccipital, parietal, and squamosal, whilst the ventral, or downwardly directed, moiety forms the posterior boundary of the tympanic cavity. The lateral segment of the foramen magnum is formed by the horizontal plate of the lateral occipital, which also, by the wTay, forms the extreme outer angle of the occipital condyle. The fact that the exoccipital comes into contact with the parietal is noteworthy : a similar relationship obtains also in Dromceus among the Palseognathae, and will doubtless be found among several other Neognathine forms. The exoccipital is only just visible, from the cranial cavity being-overlaid by the opisthotic. |