870 Mr. W. P. Pycraft on the 



neossoptiles and true nestling dowu-£eatliers (plumulse), in 

 that he remarks that the " down-feathers are more numerous" 

 than in the adult. 



Of the embryo it is stated that " on the dorsal surface the 

 feathering appeared to be quite uniform, though sparse ; 

 there was no distinct spinal apterion/^ The figure accom- 

 panying this description was drawn from a stage apparently 

 roughly corresponding to that of a 5-6-day chick embryo. 

 From a specimen apparently a few hours older (PL XI. fig. 4), 

 kindly furnished by Prof. A. Newton, I find an undoubtedly 

 distinct spinal apterium, but. as I have already remarked, the 

 precise form and limits of the pt. spinalis and pt. femoralis 

 could not be positively determined. In justice to Mr. Bed- 

 dard I should mention that this embryo was a better pre- 

 served specimen than that which he described. 



Dr. Gadow describes the branches of pt. ventralis as 

 gradually approaching each other, and at the same time 

 decreasing in width, whilst, according to my specimens, the 

 branches do not decrease, but increase as they approach the 

 cloaoal aperture. I have not found anything to support the 

 statement that much of the down upon the apteria has become 

 transformed into filoplumes. The actual number of cubital 

 remiges is 11, not 9. 



In conclusion I wish to tender my thanks to Dr. Sclater 

 for having so kindly entrusted me with this investigation, 

 and to express a hope that ere long fresh material will come 

 to hand, so as to enable us to set at rest one or two little 

 matters of detail that I have been unable to settle with 

 certainty in the present paper. 



Refei'ences. 



1. Bbddard, F. E. Contributions to the Anatomy of the 



Hoatzin, Opisthocomus cristatus, with particular refer- 

 ence to the Structure of the Wing in the Young. 

 Ibis, 1889, p. 283. 



2. Degen, E. On some of the Main Features in the Evolu- 



tion of the Bird's Wing. Bull. Orn. Club, vol. ii. 

 1894, pp. ix, X. 



