43& 



The Descent of Man. 



Part II. 



darker and darker towards the lower part of the ball. It is this 

 shadiDg which gives so admirably the effect of light shining on 

 a convex surface. If one of the balls be examined, it will be seen 

 that the lower part is of a brown tint and is indistinctly sepa- 

 rated by a curved oblique line from the upper part, which is 

 yellower and more leaden ; this curved oblique line runs at right 

 angles to the longer axis of the white patch of light, and indeed 

 of all the shading ; but this difference in colour, which cannot 

 of course be shewn in the woodcut, does not in the least interfere 

 with the perfect shading of the ball. It should be particularly 

 observed that each ocellus stands in obvious connection either 

 with a dark stripe, or with a longitudinal row of dark spots, for 

 both occur indifferently on the same feather. Thus in fig. 57 stripe 

 A runs to ocellus a ; B runs to ocellus b ; stripe C is broken in 

 the upper part, and runs down to the next succeeding ocellus, 



not represented in the wood- 

 cut ; D to the next lower one, 

 and so with the stripes E 

 and F. Lastly, the several 

 ocelli arc separated from each 

 other by a pale surface bear- 

 ing irregular black marks. 



I will next describe the 

 other extreme of the series, 

 namely, the first trace of 

 ail ocellus. The short se- 

 condary wing - feather (fig. 

 58), nearest to the body, 

 is marked like the other 

 feathers, with oblique, lon- 

 gitudinal, rather irregular, 

 rows of very dark spots. 

 The basal spot, or that near- 

 est the shaft, in the five lower 

 rows (excluding the lowest 

 one) is a little larger than 

 the other spots of the same 

 row, and a little more elon- 

 gated in a transverse direc«= 

 tion. It differs also from the other spots by being bordered 

 on its upper side with some dull fulvous shading. But this 

 spot is not in any way more remarkable than those on the 

 plumage of many birds, and might easily be overlooked. The 

 next higher spot does not differ at all from the ripper ones in 



Fig. 58. Basal part of the secondary-wing 

 feather, nearest to the body. 



