° 1915 ] VON Ihering, The Dendrocolaplidce. 147 



the premaxilla or passes above it, but does not extend to this point 

 in the holorhinal skull. It must however be observed that the 

 term schizorhinal cannot properly be applied to the members of 

 the Furnariidse because the posterior end of the nostril does not end 

 in a gap but has always a rounded extremity. For this very reason 

 Fiirbringer rejects the term schizorhinal in this connection, sub- 

 stituting for it the new term pseudo-schizorhinal, and adds that 

 both terms probably only refer to different modifications of the 

 same anatomical condition. 



We shall see this opinion amply confirmed by my studies. 

 The Synallaxinse are without exception schizorhinal as are also 

 the Furnariinse, although Geobates has the nasal foramen somewhat 

 shortened, its posterior end being situated somewhat before that 

 of the intermaxillary. 



Pronounced holorhiny is found only among the Dendrocolaptinse 

 of which, however, some genera — Sittasomus, Dendrocincla and 

 probably others — are typically schizorhinal. 



The Philydorinse (Philydor, Xenicopsis, Xenops, etc.) form a 

 transition group leading up to the Dendrocolaptinse and the species 

 are schizorhinal with the exception of Automolus and Anabazenops 

 which have the nasal foramen shortened. 



When we seek to explain the phylogenetic developments here set 

 forth, it is evident that the forms which present the greatest modi- 

 fication are the Dendrocolaptinse, which are completely adapted 

 for climbing after the manner of the W 7 oodpeckers. The extraor- 

 dinarily lengthened exterior rectrices and the protruding shaft 

 points are peculiarities which characterize them as terminal mem- 

 bers of a developmental series issuing from the Philydorinse. 



We are able to distinguish among the Dendrocolaptinse two 

 groups of genera. One of these, beginning with the schizorhinal 

 genera, Sittasomus and Dendrocincla leads by way of Dendroplex, 

 to Dendrocolaptes and Xiphocolaptes the most powerful forms of 

 the family with the heaviest beaks. The other group beginning 

 with Picolaptes leads to forms with extremely long, curved beaks 

 such as Nasica and Campylorhynchus. Xiphocolaptes as well as Dry- 

 mornis, Nasica, etc., are extremely modified members of the family, 

 of considerable size, and their peculiarities can be easily explained 

 by comparison with the structure of the smaller, less specialized, 

 forms. 



