1876.] 



ON THE ANATOMY OF CHAUNA DKRBIANA. 



189 



3. On the Anatomy of Chauna derhiana, and on the Systematic 

 Position of the Screamers (Pulamedeidce). By A. H. 

 Garrod, M.A., F.Z.S., Prosector to the Society. 



[Received January 5, 1876.] 

 (Plates XIl.-XV.) 



In his memoir "on the systematic position of the Crested 

 Screamer {Palamedea chaiuiria)" pubhshed in the ' Proceedino-s ' 

 of this Society*, Prof. Parker has placed that bird among the An- 

 seres, and away from the Rallidae, with which it had been generally 

 associated. In his " Classification of Birds "f. Prof Huxley adopts 

 the same view as Prof Parker. Both these distinguished authorities 

 base their ojjinions on anatomical considerations ; it therefore be- 

 hoves me to attempt to substantiate the different views expressed by 

 me in my paper " ou certain muscles of Birds, and their value in 

 Classification "J, as it is so considerably at variance with that of the 

 authorities just mentioned. 



The great extent to wliich the skeleton is permeated with air 

 renders the features presented by the different bones of Chuna less 

 distinctive than in the majority of birds. For this reason the soft 

 parts will be first considered. 



Cutaneous Sijstem. Fteri/fosts.—Nkzsch has described the ptery- 

 losis of Falamedea cornuta and Chauna chuvaria ; and, as might be 

 expected, C. derbiaiia does not differ in any important partfculars 

 from the latter. As he remarks, the most striking point observed in the 

 plucked bird is the extreme whiteness of the surface, which depends 

 on the fact that the skin is almost universally emphysematous to the 

 depth of nearly a quarter of an inch. On pressing' with the finger 

 the characteristic crackhng of a tissue filled with air is most marked' 

 the only places in which it is absent, or nearlvso, being the anterior 

 surfaces of the upper ends of the tibia, and, to a less degree, two 

 triangular spaces, equilateral, with their bases towards the m'iddle 

 line, situated one on each side over that part of eacii pectoral reo-ion 

 which is near the head of the humerus, in the apex of the laro-er 

 triangular surface bounded by the superior and axillary margins^of 

 the great pectoral muscle. 



In the Gaunet and the Pelican the skin is hkewise emphyse- 

 matous, but not exactly in the same way. In them the superficial 

 surface of the cutis forms a plane surface, and the deep layer 

 another, with the air-cells intervening between them, and the feather- 

 quills traversing them. lu Chauna, however, these two cutaneous 

 layers are not definable, the whole presenting the appearance as if a 

 non-emphysematous skin had been forcibly blown up, so as to cause 

 Its surface to be irregular and bubbled, more like an artificially 

 distended mammahan lung than any thing else. The feathers and 

 the semiplumes do not perforate the air-cells, but cause the skin to 

 he indented where they are situated. 

 • P. Z. S. 1863, p. 511. t P. Z. S. 1867, p. A\b. \ P. Z. S. 1874, p. 1 17. 



