296 THE CASE AGAINST EVOLUTION 



win erred in denying the utility of the vermiform appendix. 

 For, although this organ does not discharge in man the im- 

 portant function which its homologue discharges in grain-eat- 

 ing birds and also in herbivorous mammals, it subserves the 

 secondary function of lubricating the intestines by means of 

 a secretion from its muciparous glands. 



Darwin gives the semilunar fold as another instance of a 

 vestigial organ, claiming that it is a persistent rudiment of a 

 former third eyelid or membrana nictitans, such as we find 

 in birds. 'The nictitating membrane, or third eyelid," 

 he says, "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 amphibians, 

 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 some higher mam- 

 mals, 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." {Op. cit., 

 ch. I, pp. 35, 36.) Here Darwin is certainly wrong about his 

 facts; for the so-called third eyelid is not well developed in 

 the two lower divisions of the mammalian series {i.e. the 

 monotremes and the marsupials) nor in any other mammalian 

 type. ''With but few exceptions," says Remy Perrier, "the 

 third eyelid is not so complete as among the birds; (in the 

 mammals) it never covers the entire eye. For the rest, it is 

 not really perceptible except in certain types, like the dog, 

 the ruminants, and, still more so, the horse. In the rest (of 

 the mammals) it is less developed." ("Elements d'anatomie 

 comparee," Paris, 1893, p. 1137.) Moreover, Darwin's sug- 

 gestion leaves us at sea as to the ancestor, from whom our 

 "rudimentary third eyelid" has been inherited. His mention 

 of birds as having a well developed third eyelid is not very 

 helpful, because all evolutionists agree in excluding the birds 

 from our line of descent. The reptiles are more promising 



