Chap. \. 



Rudiments. 



17 



me probable that the points in question are in some cases, both 

 in man and apes, vestiges of a former condition. 



Fig 3 Foetus of an Or.in£:. Kxactcipy of .1 photfgnipL, shewing the Vi)n»i jt 

 thL^ ear at ibis early age. 



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 

 reptiles and amphibians, and in certain lishes, as in sharks. It 

 is fairly well developed in the two lower divisions of the mam- 

 malian series, namely, in the monotremata and marsupials, and 

 in some 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.°° 



The sense of smell is of the highest importance to the gn ater 

 number of mammals— to some, as the ruminants, in warning 

 them of danger; to others, as the carnivora, in finding their 

 prey; to others, again, as the wild boar, for both purposes 

 combined. But the sense of smell is of extremely slight service, 

 if any, even to the dark coloured races of men, in whom it is 



" Miiller's ' Elements of Physi- 

 ology,' Eng. translat., 1842, vol. ii. 

 p. 1117. Owen, ' Anatomy of Verte- 

 brates,' vol. iii. p. 260 ; ibid, on 

 the Walrus, 'Proc. Zoolog. Soc' 

 „foi'ember 8th, 1854. See also R. 



3 



Knox, ' Great Artists and Anato- 

 mists,' p. 106. This rudiment ap- 

 parently is somewhat larger in 

 Negroes and Australians than in 

 Europeans, see Carl Vogt, ' Lectures 

 on Man,' Eng. translat. p. 129. 



