1906.] OF THE TRACHEOPIIONE PASSERES. 135 



Fittidce. — Interorbital septum perforate; postorbital processes 

 small ; temporal fossa extending to the mid-dorsal line ; a 

 more or less well-marked nasal hinge ; maxillo-palatines in 

 the form of short thick spurs, crossing the middle of the 

 olfactory floor and far removed from the median descending 

 keel of the palatine. 



The Occvpital Region. 



The plane of the occipital forainen slopes obliquely backwards 

 through an angle of about 45°, while the foramen itself is without 

 any marked supraforaminal ridge, except in the case of the Pittidse, 

 where it is fairly pronounced. Compared with that of the 

 Eurylfemidje the cerebral fossa will be found to project slightly 

 beyond (caudad of) the foramen, instead of sloping forwards as 

 in that grouj), thereby indicating a larger brain-cavity. The 

 lambdoidal crest is not strongly marked, but the region enclosed 

 thereby is wide, except in the case of Pitta, where this ridge 

 is conspicuous and curves rapidly downwards to pass into the 

 lateral occipital wings, thus decreasing the width of the skull in 

 this region. The cerebellar dome is nowhere very prominent, 

 except in Pseudocolaptes, where it attains a develojjment far 

 exceeding that which obtains in any other member of any of the 

 families now under discussion, inasmuch as it rises upwards far 

 above the level of the lambdoidal ridge and temporal fossee to 

 form a tumid swelling, bounded on either side by the cerebral 

 lobes, which stand out in the form of bullte separated from the 

 cerebellar prominence by deep depressions. The lateral occipital 

 wings bounding the tympanic cavity are turned somewhat for- 

 wards, and tend to approach one another in the middle line more 

 than in the Euryltemidfe. This is especially noticeable in the 

 Conopophagida?, Philepittidae, Pipridfe, and Dendrocolaptidfe. 



The Crcmicd Roof (text-fig. 49 a-d). — The cerebral dome is 

 wide, well rounded, and rises gently above the cerebellar dome. 

 Pitta and Hylactes are exceptions in this respect, the cerebral 

 dome rising much higher than in any other members of the 

 families under discussion. In Pitta this dome is constricted 

 laterally by wide though shallow temporal fossae, but in Hylactes 

 this region of the skull is full and round, and the temporal fossa 

 confined to a shallow dejDression immediately above the squamosal 

 prominence. In Synallaxis, Cinclodes, and Pseudocolaptes, among' 

 the Synallaxina?, and to a less extent in Xijyhocolaptes among the 

 Dendrocolaptinfe, the cerebral dome is very markedly depressed, 

 though it is at the same time unusually broad from side to side. 

 The cranium of Pseudocolaptes is further noteworthy in that the 

 roof is marked by a relatively deep) median groove, and two lateral 

 grooves marking what answers, more or less accurately, to the 

 Sylvian fissure of the brain (text-fig. 50 g, p. 140). In the Ptero- 

 ptochidfe the form of the cerebral hemispheres is well defined, 

 laut the lateral grooves of the " Sylvian fissure " are very faintly 

 indicated. 



