402 



(leaving alone Parker's embryos, Peters' and my own dissections and 

 figures) this is a feature which can be very easily verified in any young 

 Crocodile '). Versluys was not successful in following the ligamentous 

 thread down into the mandible of Lizards and Birds, since in the 

 adult this thread is squeezed in between the pterygoid and quadrate, 

 Nervertheless it is there, better still of course in young animals, and 

 it is not likely that anyone will doubt the homology of this extra- 

 columellar-mandibular string in Lizards and Birds with that at least 

 of the Crocodiles; but I am at a loss to see what valid reasons there 

 are against homologizing this Crocodilian cartilage with that, which in 

 the Mammalia connects the mandible with the malleus. 



Here however I have to thank Gaupp for an emendation. Al- 

 though I did not exactly say so in print, I did, with others before 

 me, look upon the processus folianus s. gracilis s. anterior of the 

 Mammalian malleus as homologous with the proc. internus of the 

 Sauropsidan extra-columella. Now Broman has corroborated Koel- 

 liker's statement that the proc. Folii has originally nothing to do with 

 Meckel's cartilage, but that it develops like a membrane bone, lying 

 near the lower and inner surface of the cartilage. Both authors look 

 upon it as the vanishing remnant of the angulare. Kingsley, op. cit. 

 Fig. 5, likewise figures this element in a Pig's embryo and concludes 

 more correctly „that it develops into at least part of the processus 

 folianus". This may very well be the case. Unless the angulare has 

 vanished completely (like most of the membrane bones of the reptiUan 

 jaw) after the formation of the new squamoso-dental-joint, the angulare 

 would come to lie against the MECKEL-malleus, i. e. maudibulo-extra- 

 columellar continuation. And it is as well to remember that even in 

 many Sauropsida the angulare projects considerably beyond the man- 

 dibular joint. 



Assuming for a moment that incus = quadrate, and malleus = 

 articulare, what then becomes of the extracolumellar cartilage? It is 

 too large, too elaborate and too universal to have vanished into noth- 

 ing in the Mammalia, considering that even a miserable splint bone 

 like the angulare has not been got rid of by them. Only Gaupp has 

 seriously troubled himself about it (op. cit. p. 1139) but even he cannot 

 suggest anything better than that it may be either the latero-hyale 

 or part of Eeichert's cartilage in the Mammalia, Either of them an 

 impossible comparison. However, with my interpretation of the homo- 

 logies of the earbones, this difficulty of course does not exist. 



1) The latest verification is by Kingsley, op. cit. Fig. 16, recon- 

 struction of the auditory region in the Alligator. 



