288 Mr. F. E. Bcddard on the 



Tlie above notes upon the pterylosis of Ojjisthocoimis cris- 

 tatus^\ere written before I had read what Prof. Garrod had said 

 upon the subject in his article upon the anatomy of the bird*. 

 It is important to notice that in the three specimens dissected 

 the characters of the ventral pterylosis were much the same 

 as in my specimen ; there is therefore no room for doubt that 

 the description and figures of Nitzsch are not perfectly correct. 



Prof. Garrod, as well as Dr. Young and Mr. Brigham, 

 remarks upon a patch of thickened integument which covers 

 the surface of the carina sterni. The observations upon the 

 habits of the bird made by Dr. Young, Mr. Brigham, and 

 Mr. Quelch show that this callosity is probably due to the 

 fact that the bird flies but little, although it possesses long 

 and strong wings, but remains at rest,witli the breast touching 

 the branch of the tree. It might be suggested that this would 

 also largely account for the bare spaces in front of and behind 

 the carina sterni. If this be so the ventral apterirm would not 

 correspond to that of many other birds, but would be simply 

 due to mechanical causes acting in the lifetime of the bird. 

 Thus the feathering would be nearly continuous, a condition 

 which there is some reason for regarding as a primitive one. 

 Prof.Garrod has seemingly appreciated this main characteristic 

 of the pterylosis, as the following quotation will show (Coll. 

 Papers, p. 465) : — " Opisthocomus is one of those birds in 

 which the pterylosis is not so decisive of its affinities as in 

 many cases, the reason being that so great an amount of 

 the unfeathered spaces is protected by semiplumes. May 

 not these semiplumes in many instances be degenerated 

 feathers ? This question has never been decided, so far as I 

 am aware.'"* 



So much for the pterylosis of the adult bird. 



In the nestling the condition is much the same, but the 

 down-feathers are more numerous. 



The feathering of the young chick was examined with great 

 care, in order, if possible, to throw some light upon the ques- 

 tion of the apparent continuity of the feathering. I find 

 that the ventral apterion is as conspicuously develoj)ed as in 

 * Loc. cit. p. 110 (Coll. Papers, p. 466). 



