SECOND DAY'S SITTING. 51 



Lord C. Natural Selection would thus seem to be rather 

 fond of developing points on the ear. But those additional 

 points to which you direct attention, are probably of some 

 use to us. 



Homo. Your Lordship forgets that Mr. Darwin considers 

 the whole exten al shell of the ear to be a rudiment, and 

 therefore useless. 



Darwin. My Lord, " 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 eyeball. It is found in some reptiles, and amphi- 

 bians, and in certain fishes, as in sharks. It is fairly well 

 developed in the two lower divisions of the mammalian 

 series, namely, in the Monotremata and Marsupials, and in 

 borne few of the higher mammals, as in the walrus. But 

 in man, the quadrumana, and most other mammals, it exists, 

 as is admitted by all anatomists, as a mere rudiment, called 

 the semilunar fold." (Vol. i. p. 23.) 



Homo. As with man's ears, my Lord, so with his eyes. 

 Why should they not be modelled after the type of pre- 

 ceding forms ? Mr. Darwin ttlls us that this membrane 

 is of " much functional importance to birds, as it can be 

 rapidly drawn across the whole eyeball." But this is only 

 like telling us that the eye is of much functional importance 

 to them, as they can see with it ; or the wing, as they can 

 fly with it ; or the stomach, as they can digest their food 

 with it. Mr. Darwin should rather have told us how it 

 comes to pass on the principle of Natural Selection, that 

 while birds and sharks and kangaroos have this membrane, 

 men and monkeys should be destitute of it. Their having 

 the semilunar fold can easily be accounted for by the 



