138 MR. W. p. PYCRAFT ON THE OSTEOLOGY [Feb. 20^ 



however, this wing comes to a sudden stop when it reaches the 

 summit of the curve, then turns abruptly downwards in the form 

 of a sharp ridge, losing itself in the jjrocessus articularis sqaamosi 

 (text-fig. 49 b, p. 136). 



The postorbital region is by no means uniform in character. In 

 the Pittidfe alone wide but shallow temporal fossas meet to form a 

 narrow sagittal crest. In the Conopophagidte, the Formicariida?, 

 and Dendrocolaptid^e (text-fig. 50 b-d, p. 140) temporal fossae are 

 sufliciently deep to form a fairly conspicuous squamosal pro- 

 minence, but they do not meet as in the Pittidfe. In the 

 Philepittidje these depressions are barely traceable. 



The postorbital process is obsolete in the Acanthosittidee, 

 Pteroptochinte, and Philepittidse, and in some of the small Dendro- 

 colaptinse (e. g., Xiphorhynchus). In some Formicariina? (e. g., 

 Thamnophilus) and in some Synallaxinpe (e. g., Synallaxis) this 

 process is continued downwards to fuse with the zygomatic 

 process of the squamosal, forming thereby a bony bar across the 

 temporal fossa. 



The lachrymal is either altogether wanting or is vestigial. In 

 the Piprida? this bone is small, dumbbell- shaped, and pressed against 

 the outer border of the swollen antorbital plate as in the Cotingidse. 

 It lacks an orbital process, lies entirely within the lachrymo-nasal 

 fossa, and is perforated by a pneumatic foramen. In the Ptero- 

 ptochinae it has almost completely fused with the antorbital plate 

 and is sigmoidally curved. In the Philepittida? it is represented 

 only by a minute nodule of bone lying in the superior angle of 

 the lachrymo-nasal fossa aird adherent to the antorbital plate. 



The Ethmoidal liegion. — The interorbital septum is complete 

 only in the Dendrocolaptinpe. The antorbital plate does not 

 present any very striking changes of form. In the Pteroptochiiife 

 the ventral border of this plate is deeply notched ; its outer border 

 convex and produced downwards at its inferior angle into a small 

 spur resting on the quadrato-jugal bar : in the Philepittidte it is 

 hamulate in shape. The head of the hammer is large, inflated, 

 projects downwards below the level of the quadrato-jugal bar into 

 which it fits by a groove, while the shaft of the hammer is 

 attached at right angles to the mesethmoid and so as to have a 

 clear space above and below it. In the Piprida? it resembles that 

 of the Cotingidae — as might be supposed. Oblong in shape, its 

 dorsal border is sinuously curved, leading into a space between 

 itself and the frontals, its inferior border is straight, but the 

 line is broken by the downward extension of the infero-external 

 angle ; the outer free border is hollowed. In Pittidfe the dorsal, 

 external, and ventral borders are fairly deeply hollowed, so that 

 the plate has a bilobed appearance, and this shape is still more 

 pronounced in the Dendrocolaptin*. In the Formicariinte this 

 plate is almost quadrangular in form, and has the infero-external 

 angle produced into a long pillar extending down the quadrato- 

 jugal bar : in the lai'ger forms (e. g., Batara) this column appears 

 to spring from the middle of the inferior border. In the 



