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Show 1906.] OP THE TRACHEOPHONE PASSERES. 145 form a series of separate upstanding plates, or may, on the hand, interlock one with another by means of a bifurcating process from the anterior and posterior angles of the dorsal border. In a skeleton of Siptornis sp. inc. three of these vertebra? (1-3) have become anchylosed, but whether this is an individual peculiarity or is a feature peculiar to the genus I am at present unable to say. The last thoracic, in all the species of the groups here dealt with, has fused with the synsacrum, and in the Dendrocolaptina? two thoracics appear to be generally fused therewith, each of which bears long ribs (see p. 146). Hypapophyses in the Pittida? are wanting; in no case is there more than two of these processes. In the Hylactina? and Dendrocolaptina? they are fairly well developed, but never so long as those of the two cervico-thoracic vertebra? immediately preceding. In the Piprida? and Philepittida? they are degenerate. Philepitta, by the way, is remarkable for the small size of the centra. Twelve vertebra? enter into the composition of the synsacrum, but the series from which these are drawn is not always the same, as may be seen by the following tables:- Conopophagid.r, Pitta. Piprida?. e. g., Hylactes. Philepittida?. Thoracic 1 1 1 1 Lumbar 2 2 2 3 Lumbo-sacral ... 3 3 3 3 Sacral 2 [caudal. 2 2 2 Caudal 4 + 7 free 3 + 8 3 + 8 3 + 8 12 11 11 12 Total 19. Total 19. Total 19. Total 20. Forniicariime. Dendrocolaptina?. Synallaxina. Thoracic 1 2 1 Lumbar 3 2 3 Lumbo-sacral ... 2 2 2 Sacral 2 2 2 Caudal 4 + 8 4+7 4-|-8 12 12 12 Total 20. Total 19. Total 20. The analyses here given are undoubtedly worth publishing, if only as a basis for further work; but before they can be'of any great value a comparison of a much larger series of skeletons than I have been able to make is necessary. The ventri-laterai processes of the second lumbar are in all cases well developed, but those of the sacrals are more feeble, so that some difficulty is experienced in distinguishing, superficially, between sacral and postsacral vertebra?. The dorsi-lateral processes of the sacral and postsacrals are long, keeping the innominates wide apart, PROC ZOOL. Soc-1906, VOL. I. No. X. 10 |