98 BRITISH BIRDS. 



Anteriorly, it should be remarked, the spinal tract ex- 

 pands immediately behind the scapula, and, running 

 outwards, joins the posterior border of the humeral tract: 

 from thence it becomes continuous with the pteryla 

 femoralis. In the region covered by the closed wing the 

 feathers are very small, but only in what is practically 

 the axilla have they disappeared. Just as the pteryla 

 femoralis is continuous with the pteryla spinalis above, 

 so it is also continuous with the pteryla ventralis below. 



There are 11 primaries, and 18 rectrices. 



There are yet other features in connection with the 

 Pterylosis of tins bird which have long puzzled me, and 

 the most elusive of these concerns the nature of the 

 feathers of the neck during the adult and winter 

 plumages. On this theme, and on one or two minor 

 points, I hope to have something to record in the near 

 future. But I would draw attention here to the webbing 

 of the feet, for I find, on careful examination, that the 

 foot approaches that of the Steganopodous type, since 

 the hallux is bound by a very distinct web to the base 

 of the inner toe, and this web, it seems to me, should be 

 regarded as a vestige of a thin sheet of membrane 

 extending between the hallux and inner toes, as in the 

 Steganopodes. An examination of the feet of nestlings, 

 or embryos, may show that this web, during earlier 

 stages of development, is more extensive than in the 

 adult. 



In considering the Pterylosis of the Divers one turns 

 naturally to that of the Grebes for comparison. And 

 here, as with the Divers, all figures so far published, 

 seem to be inaccurate. I have just completed a study of 

 the Dabchick from this point of view, and was surprised 

 to find how far from the truth are the descriptions here 

 referred to. When I have made a similar examination 

 of the Great Crested Grebe I propose to communicate the 

 results to the pages of British Birds. 



