1906.] OF THE TRACUEOPHOXE PASSERES. 145 



form a series of separate upstanding plates, or may, on the other 

 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 vei'tebraa (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 Dendi'ocolaptinaj two 

 thoraeics appear to be generally fused therewith, each of which 

 bears long ribs (see p. 146). Hypapophyses in the Pittidee are 

 wanting ; in no case is there more than two of these processes. 

 In the Hylactin^e and Dendrocolaptinee they are fairly well 

 developed, but never so long as those of the two cervico-thoracic 

 vertebrfe immediately preceding. In the Pipridre and Philepittidse 

 they are degenerate. Philepitta, by the way, is remarkable for 

 the small size of the centra. 



Twelve vertebr?e 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 : — 



The analyses here given aie undoubtedly worth publishing, if 

 only as a basis for further work ; but before they can be of 

 any gi'eat value a comparison of a much larger series of skeletons 

 than I have been able to make is necessary. The ventri-lateral 

 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 saci'al and 

 postsaci-al vertebrae. The dorsi-lateral processes of the sacral 

 and postsacrals are long, keeping the innominates wide apart, 



Puoc. ZooL. SOC.--1906, Vol. I. No, X. 10 



