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Show 452 PROF. HUXLEY ON THE CLASSIFICATION OF BIRDS. [Apr. 11, In Tyrannus, in Cephalopterus, in Coracina (according to Burmeister), and perhaps in others of the American Passerines without a singing-apparatus, the bases of the maxillo-palatines are broader than their free ends, and there is no narrow stem. Chasmorhynchus nudicollis, however, has maxillo-palatines of the ordinary character; and in Pteroptochus megapodius they are long, slender, and recurved. In Gymnorhina the septo-premaxillary ossification and the maxillo-palatines are confluent, though the latter and the vomer remain quite distinct from one another. In these and the majority of typical Passerine birds the palatine bones are broad and comparatively flat posteriorly; but in the Finches the outer lamina of each palatine acquires a great downward development, and becomes a vertical plate, the free posterior edge of which is more or less notched. The anterior process of the palatine at the same time broadens out, and becomes connected by a truncated edge with the rostrum, which attains great height and breadth, and is sometimes hooked anteriorly. The palate thus acquires a singular superficial resemblance to that of a Parrot, from which it differs, however, in the separation of the palatines in the middle line, in the form and size of the vomer, and in the slender, recurved, and separate maxillo-palatines (fig. 33). Under view of the skull of Coccothraustes vulgaris. The letters as before. Pipra erythrocephala and Tanagra cyanoptera are similar to the Finches in the form of the palatines. The Swallows completely agree with the other Passerine birds in the general form and arrangement of the bones which enter into the composition of their palates. And the Swifts essentially resemble the Swallows, though the form and proportions of the palatine bones are somewhat different (fig. 34). The skull of Caprimulgus, though it retains the general features of the Passerine cranium, departs from the typical Passerine structure still further than the Swifts, the body of the'palatines havino-become exceedingly broad and flattened out, while the vomer is |
