138 MR. W. p. PYCRAFT OX THE OSTEOLOGY [Feb. 20, 



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

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

 of a sharjj ridge, losing itself in the processus articularis sqaamosi 

 (text-fig. 49 b"^ p. 136). 



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

 the Pittidje alone wide but shallow temporal fo.ssfe meet to form a 

 narrow sagittal crest. In the Oonopophagidfe, the Formicariidse, 

 and Dendrocolaptidi^ (text-fig. 50 b-d, p. 140) temporal fossee are 

 sufficiently deep to form a fairly conspicuous squamosal pi'O- 

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

 Philepittidfe these depressions are barely traceable. 



The jiostorbital process is obsolete in the Acanthosittidse, 

 Pteroptochinje, and Philepittidpe, and in some of the small Dendio- 

 colaptinse (e. g., Xiphorhjjnch'us). In some Formicariime (e. g., 

 ThamnopMliis^ and in some Synallaxina; (e. g., Sijnallaxis) this 

 process is continued downwards to fuse with the zygomatic 

 process of the squamosal, forming theieby a bony bar aci'oss the 

 temporal fossa. 



The lacli/rymal 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 Cotingidfe. 

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

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

 ptochinfe it has almost completely fused with the antorbital plate 

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

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

 the lachrymo-nasal fossa and adherent to the antoi-bital j^late. 



The Ethmoidal Begiov. — The interorbital septum is complete 

 only in the Dt!ndiocolaptin?e. The antorhital p>late does not 

 present any very striking changes of form. In the Pteroptochina? 

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

 convex and produced downwards at its infeiior angle into a small 

 spur resting on the quadi'ato-jugal bar : in the Philepittida^ 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 haA'e a 

 clear space above and below it. In the Pipridoa it resembles that 

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

 doi'sal border is sinuously curv^ed, 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 Dendi'ocolaptinfe. In the Formicariina? 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 laiger forms (e. g., Batara) this column appears 

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



