ON THE QUADRATE IN THE MAMMALIA. 177 



a secondary condition. The hyoid arch applies itself to the 

 malleus, is bound to it by connective tissue, and perhaps even 

 fuses with it. The fibres of the hyoid arch are soft, and have 

 a different direction from those of the stapes-cartilage (malleus), 

 the harder fibres of which cross those of the hyoid arch. The 

 swelling of the hyoid arch at the point where it joins the outer- 

 most part of the malleus is only apparent, arising not from the 

 cartilage but from the connective tissue. According to Peters, 

 the hyoid bone is, indeed, not connected with the inner process 

 of the malleus, but passes below it, without adhering to it, so 

 that the space between the outer and inner parts of the malleus 

 is not, as Huxley thought, transformed into a foramen by a 

 junction. According to him there is no doubt that at earlier 

 stages Meckel's cartilage is connected with this inner hatchet- 

 shaped process of the malleus by means of a fibre passing along 

 the inner side of the quadrate. 



According to Peters, therefore, the stapes-cartilage, i. e. 

 the malleusof Sphenodon, is derived from the first 

 visceral arch. 



It is seen that the opinions on this very important point are 

 very various. It is strange that Parker, too, in his many 

 works on the development of the skull in Vertebrates, makes 

 no mention of this work by Peters. Besides Hoffmann, 

 Balfour mentions this point. He says (1. c, p. 483), " The 

 strongest evidence in favour of Huxley's and Parker's view of 

 the nature of the columella is the fusion in the adult Sphenodon 

 of the upper end of the hyoid with the columella (Huxley). 

 From an examination of a specimen in the Cambridge museum 

 I do not feel satisfied that the fusion is not secondary, but 

 I have not been able to examine the junction of the hyoid and 

 columella in section." 



Balfour was inclined to adopt Peters's view : I can do the 

 same. In fact, Peters is right. The malleus (stapes- 

 cartilage) is not derived from the hyoid arch : the 

 connection with it is secondary: the malleus of 

 Sphenodon and all Sauropsida is a derivative of the 

 first visceral arch. 



VOL. XXVIII, PART 1. NEW SER. M 



