No. 2304. REPTILIAN CHARACTERS IN MAMMALS— WORTMAN. 43 



Tested by these characters, where do the extinct Gynodonts stand ? 

 Comparatively little is known of the auditory apparatus in these 

 forms, but such information as has been recovered seems to point in 

 the direction of the Sauropsida and not the Mammalia. Tliis is 

 shown by the styliform condition of the stapes, alluded to above, 

 which is known in some of them at least, and which resembles that 

 of Splienodon. As the styliform stapes goes with the hyoid attach- 

 ment, as well as the absence of any element corresponding to the 

 incus, with its peculiar and characteristic relations to the prootic 

 the inference would naturally be that their real affinities are with 

 Sauropsida rather than with the mammals. If these characters are 

 true of all of them, then they would constitute an insurmountable 

 l)arrier and com.pletely shut them out from any further consideration 

 as ancestors of the Mammalia, it matters little what other mamma- 

 lian characters they may have possessed. 



There are not v^^anting among investigators of the present day 

 many who loudly proclahn the Gynodonts to be the long-sought 

 ancestors of the Mammalia, bat until such time as the important 

 matters herein discussed can be thoroughly cleared up and disposed 

 of, we must reserve our judgment and await future discoveries. At 

 all events as shown above, the monstrously improbable, if not alto- 

 gether wholly impossible hypothesis of the intercalation of the quad- 

 rate and articular into the mammalian auditory chain, can not serve 

 any purpose other than to befog the issue and prevent any clear 

 understanding of the subject. It may well be that we shall yet liave 

 to go back directly to the Batrachia to find the beginnings of the 

 Mammalia, as Huxley long since pointed out with such masterful 

 skill. This view has been subsequently defended by Kingsley. 



In the study of the foregoing subject I have consulted the following 

 papers, other than those specifically mentioned in the footnotes of 

 the text, namely, the numerous papers by Gaupp, the highly impor- 

 tant contributions by Gadow, as well as those by Broom, Fuchs, 

 and others. 



Some ])robable causes for the disappearance of the quadrate. — Taking 

 the quadrate of an average reptile like that of ^^;?igno(^07i (figs. 14,15,16) 

 it is to be observed that it is solidly attached to the cranium by a 

 series of bony arches, bars, and braces, which give firm support to 

 the articulation of the lower jaw. Above and to the inside it is 

 attached to the lower end of the temporo-occipital arch, furnished 

 principally by the squamosal, where it is stoutly braced from within 

 by an outward projection of the exoccipital. Upon the outside, on a 

 level a little above the articulation, it is braced in front by the quadra- 

 tojugal bar, and above by a depending process of the squamosal. Run- 

 ning forwards and inwards from the articular joint is a broad stout 

 vertical lamella of bone which unites with the pterygoid constituting 



