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Show 1899.] CRANIAL OSTEOLOGY OF THE PARROTS. 15 in a broad, somewhat excavated shelf to overlap (as well as to project in front of) the head and upper portion of the shaft of the quadrate bone. This squamoso-zygomatic plate is deeply hollowed on its outer face, suggesting perhaps the presence of a highly specialized muscle (probably the second portion of the digastric) originating there. The lower border of the overhanging shelf is slightly bilobed, especially in another specimen in m y collection from that figured. The posterior portion or posterior lobe, and perhaps the whole hollow on the outer face of the bone, may be considered to be an extension of the region internal or anterior to the " suprameatal " process of Mivart, a region which in most Parrots forms only a small facet; its aspect here, together with the general conformation of the bone, reminds us h o w in a Lizard the squamosal tends to overlap the outside of the quadrate in a way which culminates in the great descending limb or process of the bone that bounds the infratemporal arcade in Hatteria. I know no other bird in which a very similar condition of things is to be seen; but w e may discover in some Passerines, e. g. the Raven, a certain correspondence of parts. If we trace in the Raven (fig. 4) the ridges and muscular impressions on the postero-lateral surfaces of the skull, we see (1) on the upper margin of the supra-occipital region two curved trans- Fig. 4. Corvus corax, to show diagrammatically the muscular fossae and intervening ridges. s.m., suprameatal tubercle; sq., squamosal; t. temporal, d. digastric fossa; d.', fossa for second head of the digastric, in front of s.m., the suprameatal tubercle. The ridges or outlines of the muscular impressions are described in the text. verse ridges which run outwards from the middle line to a tubercle (a) posterior to and nearly on a level with the upper border of the auditory meatus; (2) an undivided ridge curves downwards from |