On the Anatomy of Acanthidositta chloris. 603 



XXXIX.- — Some Points in the Anatomy of Acanthidositta 

 chloris, with some Remarks on the Systematic Position of the 

 Genera Acanthidositta and Xenicus. By W. P. Pycraft, 

 F.Z.S., A.L.S. 



(Plate XIII.) 



Introductory. 



Only one other paper — by the late W. A. Forbes — has ever 

 been published dealing with the anatomy of the aberrant 

 and little-known forms Acanthidositta and Xenicus. In this 

 paper the author dials only with the syrinx, patagial muscles, 

 and skull and podotheca. 



While Forbes devoted his attention primarily to Xenicus, 

 though he dissected specimens of both genera, I have per- 

 force had to confine my investigations to Acanthidositta ; 

 but probably it will be found that Xenicus does not differ 

 therefrom in any important particular. In so far as the 

 syringes of these two genera are concerned, Forbes assures us 

 that in "all points Acanthidositta appears to agree (with 

 Xenicus) in every essential respect." 



I have been enabled to bring to light some extremely 

 interesting facts concerning Acanthidositta, which in some 

 cases seem to conflict with the statement made by Forbes 

 some seven-and-twenty years ago. 



For the material on which this work is based I have to 

 thank my kind friends Mr. W. R. Ogilvie-Grant and 

 Mr. F. E. Beddard, F.R.S. 



Pterylography. 



Pteryla capitis (text-fig. 34, pt.cap., p. 604). — This extends 

 from the base of the culmen backwards in the form of a narrow 

 band between the eyes, which are prominent, to expand so 

 as to cover the parietal and occipital region of the cranium, 

 and sweeping downwards passes forwards along the lower 

 jaw. From its origin at the culmen the tract branches out 

 on either side to the lores, and this wing extends backwards 

 over the eyelids near its free edge, leaving a bare space 



