ANATOMY OP THE SHOE-BILL. 645 



careful account of the external characters and pterylosis, but 

 fortunately I finished my examination and notes of the pterylosis 

 before having the oppoi'tunity of consulting Professor Giebel's 

 paper, and find that my observations and inferences follow his 

 very closely. 



The down feathers are distributed practically uniformly over 

 the pterylae and the apteria as in Steganopods and Storks, where- 

 as in Scopus and Herons they are found only on the apteria. 

 The oil-gland has a tuft of feathers as in nearly all the members 

 of the group. The contour feathers have a small aftershaft ; 

 this structure is present in Herons and S'copus, variable and 

 sometimes absent in Storks. 



The feathered tracts generally are in marked contrast Avith those 

 of Herons and resemble those of Storks in being relatively wide 

 and fading off into the apteria, those in Herons being remarkably 

 narrow and very sharply defined at their lateral and posterior 

 edges. The neck is continuously feathered for almost the whole 

 of its length, and shows no trace of the long lateral apteria 

 characteristic of Herons and present in Scopus. Far back, near 

 the base of the neck, there is a lateral space at each side. The 

 spinal tract forks between the shoulders, leaving two parallel bands 

 of feathers continuous with the neck area, and separated by a 

 wide median apterion. These dorsal bands are wider than those 

 of Herons and cease about the level of the axilla. Parallel with 

 them at each side is a very broad and strong humeral tract, wider 

 even than in Storks and much wider than in Herons. The dorsal 

 tracts reappear again as a narrow diamond-shaped band, weaker 

 in the middle line, and stretching between the powder-down 

 patches to the oil-gland. The powder-down patch at each side is 

 an enormous, elongated oval area extending from a little way 

 behind the axilla to the rectrices, and reaching some way down 

 the side of the rump. The patches are sejoai-ated in the middle 

 line. The feathei's are long, very thickly set, and break down 

 into a yellowish powder. When the bird had been in spirit, they 

 formed unpleasant, greasy masses. Their discovery led Bartlett 

 to associate Balceniceps with Herons as opposed to Storks. As, 

 however, there are only two patches in Balceniceps as compared 

 with four to six in Herons generally, eight in Cancroma, 

 as they are absent in Scopus and exist in many other birds, 

 e. g. Eurypyga, Rhinochetits, Mesites, some Tinamus, Birds of 

 Prey, Parrots, and Goatsuckers, it is difficult to attach any 

 systematic weight to their presence. Nitzsch's observation that 

 they may disappear with age (e. g. Gypaetus) still further destroys 

 their systematic importance. 



The femoral tracts bordering the powder-down patches are 

 rather badly defined. The arrangement on the ventral surface is 

 almost identical with that given by Nitzsch for Ciconia. The 

 median apterion is rather indefinite except at the base of the 

 neck and near the vent. On each side of it is a veiy broad 

 feathered tract. 



43* 



