410 



why their articulare should possess such a huge bent-dowii hook; or 

 is this a "Versuch" or "Vorahnuug" of the future manubrium? 



The quadrate is supposed to become the incus, since the lateral 

 end of the Amphibian and Reptilian "stapes" sometimes leans onto 

 the quadrate. And where is this feature carried out to perfection? 

 In Gymnophiona, Plesiosaurs, Chamaeleons and Snakes, every one of 

 which groups represents a most specialised, terminal branch of the 

 evolutionary tree. And even in Snakes I have shown the persistence 

 of an extracoluniella, or is this to be homologized with the leutiform 

 ossicle? — But this lean-to feature was never the real reason for 

 homologiziug the quadrate with the incus. The true reason was the 

 continuity of the malleus with Meckel's cartilage which in the em- 

 bryonic mammal seems to demonstrate the homology of the malleus 

 with the articulare. This change of course necessitates the formation 

 of a new biting joint, but this new squamoso-dental joint is developed, 

 as I have shown, laterally and above the old joint, not distally from 

 it; and the distal position must be, and is assumed by those who 

 want to see the articulare set free as the malleus. 



Let us examine what terrible intermediate stages this would imply. 



Jl^cxo-moS:. 



<L^=^ 



A-Ufui. 



Fig. 6. The critical stage duiiug which the Promixmnial could not use its jaw 

 and could not hear. 



A lever-bar, the mandible, supported at two places, one behind the 

 other in the long axis. Such a thing would not be able to move; 

 the animal could not use its jaws, and this intermediate stage would 

 also imply the giving up of hearing through the tympauum and through 

 the columellar or stapedial apparatus, until the quadrate, relieved of 

 its suspensorial function, had slipped in with the articulare (malleus) 

 and had reestablished the connexion between stapes and tympanum! 

 The latter had to give up its attachment to the quadrate (as existing 

 in Anura, Reptiles and Birds) and wait for the quadrato-jagal to turn 

 round and take the quadrate's place 1 Well is it said in Gegenbaur's 



