16 THE DESCENT OF MAN. 



one of mere variability; and that the projections are not real 

 ones, but are due to the internal cartilage on each side of the 

 points not having been fully developed. I am quite ready to 

 admit that this is the correct explanation in many instances, as 

 in those figured by Prof. Meyer, in which there are several minute 

 points, or the whole margin is sinuous. I have myself seen, 

 through the kindness of Dr. L. Down, the ear of a microcephalous 

 idiot, on which there is a projection on the outside of the helix, 

 and not on the inward folded edge, so that this point can have 

 no relation to a former apex of the ear. Nevertheless in some 

 cases, my original view, that the points are vestiges of the tips 

 of formerly erect and pointed ears, still seems to me probable. I 

 think so from the frequency of their occurrence, and from the gen- 

 eral correspondence in position with that of the tip of a pointed 

 ear. In one case, of which a photograph has been sent me, the 

 projection is so large, that supposing, in accordance with Prof. 

 Meyer's view, the ear to be made perfect by the equal development 

 of the cartilage throughout the whole extent of the margin, it 

 would have covered fully one-third of the whole ear. Two cases 

 have been communicated to me, one in North America, and the 

 other in England, in which the upper margin is not at all folded 

 inwards, but is pointed, so that it closely resembles the pointed 

 ear of an ordinary quadruped in outline. In one of these cases, 

 which was that of a young child, the father compared the ear with 

 the drawing which I have given" of the ear of a monkey, the 

 Cynopithecus niger, and says that their outlines are closely sim- 

 ilar. If, in these two cases, the margin had been folded inwards 

 in the normal manner, an inward projection must have been 

 formed. I may add that in two other cases the outline still re- 

 mains somewhat pointed, although the margin of the upper part 

 of the ear is normally folded inwards — in one of them, however, 

 very narrowly. The following woodcut (No. 3) is an accurate 

 copy of a photograph of the fcetus of an orang (kindly sent me 

 by Dr. Nitsche), in which it may be seen how different the pointed 

 outline of the ear is at this period from its adult condition, when 

 it bears a close general resemblance to that of man. It is evident 

 that the folding over of the tip of such an ear, unless it changed 

 greatly during its further development, would give rise to a point 

 projecting inwards. On the whole, it still seems to me probable 

 that the points in question are in some cases, both in man and 

 apes, vestiges of a former condition. 



The nictitating membrane, or third eyelid, with its accessory 

 muscles and other structures, is especially well developed in 

 birds, and is of much functional importance to them as it can 

 be rapidly drawn across the whole eye-ball. It is found in some 



" 'The Expression of the Emotions,' p. 136. 



