'14G MR. W, p. PYCRAFT OX THE OSTEOLOGY [Feb. 20, 



Avhile by the ossification of the tendinous tissue overlying them a 

 bony roof to the pelvis is formed, which is most complete in Pitta 

 (see p. 151). 



In Pitta the fourth postsacral forms a pai-t of the synmcrum, 

 although it really lies well behind the embiace of the irniominate ; 

 on the other hand, in Xiphocolapies, for example, the fifth free 

 caudal lies within this embrace, yet remains free. 



Well-marked intercentra, as might be expected, occur in the 

 Dendrocolaptime — 5 to 7 vertebr.-e ; they are smaller in the Synal- 

 laxinfe and Formicaiiin?e, and vestigial or wanting in the Pipridse 

 and Philepittida?. 



The venti-al aspect of the synsacrum is marked in a way which 

 deserves some notice, inasmuch as it may be either deeply 

 grooved or pitted, after a fashion apparently not met with outside 

 the groups in which these peculiaiities occur. 



Thus in the Pipridse the ventral aspect of the synsacrum is 

 marked by deep grooves extending on either side of the middle 

 line from the level of the first lumbar to the sacral vertebra? ; 

 while in Pipra there will be found a double row of deep oblong 

 pits, one along either side of the middle line, from the last 

 thoracic vertebra (the synsacral) to the first sacx^al. Among the 

 Synallaxinre, Siptornis agrees with Chiroxiphia, while Synallaxis 

 agrees with Pipra. The Hylactina^ have a grooved synsacrum. 



These pittings appear, indeed, to occur only in the Pipridfe, 

 Synallaxinse, and Acanthidosittidae, and may extend, as in Pipra, 

 along the whole length of this complex as far as the first sacral, 

 or may occur only fiom the last lumbar to the fiist sacial, as in 

 Cinclodes. 



iv. The Ribs. 



In the Pipridse, Pittida', Philepittida', Conopophagida^ and 

 Formicariina^ h)ng styliform I'ibs are borne by the cervical 

 vertebra", from the r)th to the 9th inclusive; from the 10th-12th 

 the style is vestigial and a narrow pleuiapophysial lamella alone 

 is left. The Dendrocolaptina? differ in having the styliform 

 portion of the rib much shorter than in the types just referred to. 

 Among the Synallaxinte it would seem that two types of ribs 

 obtain, one represented by a band-like pleurapophysial lamella, 

 and one in which this is very broad, and may further have a short 

 style as in Xiphorhynchus. 



There are three cervico-thoracic ribs, the 1st greatly reduced ; 

 the 3rd bears an uncinate process but no sternal segment. 



There are six thoracic ribs, of which five generally articulate 

 with the sternum. In some of the Synallaxinse and Dendi-o- 

 colaptinse there is a tendency for the 5th rib to lose its connection 

 with the sternal border. The 6th rib, almost invariabl}'^ articulates 

 with the sternal segment of the .5th, being attached by ligament 

 to a more or less well-defined facet. 



The uncinates are generally moderately long and slender, only 

 in Pitta are they conspicuously bioad. 



