508 HISTORY OF PHYSIOLOGY. 



beaks, was shown, by the assumed posture, to have 

 its upper mandible longer than the lower, and thus 

 to be regularly placed. " But," says Cuvier 13 , "sup- 

 posing the posture, in order that the side on which 

 the funnel of the sepia is folded should be the back 

 of the animal, considered as similar to a vertebrate, 

 the brain with regard to the beak, and the oeso- 

 phagus with regard to the liver, should have posi- 

 tions corresponding to those in vertebrates; but 

 the positions of these organs are exactly contrary 

 to the hypothesis. How, then, can you say," he 

 asks, "that the cephalopods and vertebrates have 

 identity of composition, unity of composition, with- 

 out using words in a sense entirely different from 

 their common meaning?" 



This argument appears to be exactly of the 

 kind on which the value of the hypothesis must 

 depend 14 . It is, therefore, interesting to see the 

 reply made to it by the theorist. It is this : " I 

 admit the facts here stated, but I deny that they 



13 G. S. H. Phil. Zool. p. 70. 



14 I do not dwell on other arguments which were employed. 

 It was given as a circumstance suggesting the supposed posture 

 of the type, that in this way the back was coloured, and the 

 belly was white. On this Cuvier observes ls , " I must say, that 

 I do not know any naturalist so ignorant as to suppose that the 

 back is determined by its dark colour, or even by its position 

 when the animal is in motion ; they all know that the badger 

 has a black belly and a white back ; that an infinity of other 

 animals, especially among insects, are in the same case; and 

 that many fishes swim on their side, or with their belly upwards." 



15 Phil Zool. pp. 93, 68. 



