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Show 890 DR. R. W. SHUFELDT ON THE OSTEOLOGY OF THE [D A pterygoid is a delicate and nearly straight rod of bone, articulating with the palatine in the manner just described, and with the corresponding quadrate by means of a cup-and-ball joint, the latter element developing the convexity for the purpose. The rostrum is transversely very broad behind, where it is likewise longitudinally excavated. As it is produced forwards, however, it ascends, becoming gradually narrower, convex from side to side, to finally abut against the under aspect of the cranio-facial region, where we find that its anterior margin has at last attained a sharp edge. It is unnecessary to add, that this latter portion of the rostrum is made up of the ethmoidal bone, the two imperceptibly merging into each other in the Humming-birds. Some of the characters thus far described, as they are found to exist at the under side of the skull of Trochilus, are curiously suggestive of the struthious type of structure, more especially the exposed and broad rostrum behind, and the method of finishing off of the maxillaries and maxillo-palatines in front. T. alexandri has the basi-temporal region of its skull very deep, and wide from side to side. It is pierced at about the usual sites by foramina for nerves and vessels to find their exit from, and others to enter the cranial casket. The plane of the foramen magnum is nearly coincident with that of the basis cranii; and this aperture is very large comparatively, and of a broad elliptical outline. On the other hand, the condyle is notably minute in its dimensions, and of a hemispheroidal form. The mandible of the Alexander Humming-bird is seen upon lateral view in Plate LVIII. fig. 2. It will be observed that it is quite as delicately fashioned as the remaining half of the beak above. Its hinder fourth is bent downwards, and a well-marked ramal vacuity exists. Viewed upon its superior aspect, this bone has a very acute V-shaped outline, with rather a long symphysis, which latter is excavated in the longitudinal direction above. Either articular end presents a very shallow facet on its upper side; behind, its angle is truncated, while the in-turned processes of the ramal limbs at this extremity are well developed and point directly towards each other, being perpendicular to the median plane. This bone is largely pneumatic. The elements of the hyobranchial apparatus are absolutely filamentous in character, the greatly lengthened thyro-hyals curving well up behind the occiput, after the style of some Woodpeckers. The first basi-branchial is very long and straight, while the second one is reduced to a mere rudiment ; both are independent bones and the heads of the ceratobranchials articulated at the sides, where they meet each other. The ceratohyals and glossohyal do not ossify in this Hummingbird. Having examined the skeleton of Trochilus thus far, I will now briefly present the characters of the same part as they are found in the two remaining groups, taking up the Goatsuckers first. After that, it is m y intention to discuss the balance of the axial skeleton |