ON THE QUADRATE IN THE MAMMALIA. 179 



more especially on Gecko, strengthens this view. In both the 

 hyoidarch is complete, but has absolutely nothing to do with 

 the malleus. But the proof that the hyomandibular is equivalent 

 to the epimandibular adds strength to Albrecht's other hypo- 

 thesis, that the quadrate originally belonged to the palatine 

 arch and not to the mandibular arch. 



I will now speak of the quadrate itself. That it cannot be 

 looked for in one of the auditory ossicles follows clearly from 

 the foregoing. 



According to Tiedernann, Platner, Kostlin, Duveruoy, and 

 Albrecht, the quadrate of mammals is equivalent to the zygo- 

 matic process of the squamosal. I agree fully with this view. 

 To the examples adduced by Albrecht and Duvernoy of an 

 actual separation I can add a further one. In a stillborn tiger 

 I found in the right squamosal very much the same condition 

 of things as Albrecht has described in the skull of a newborn 

 child. The zygomatic process is separated by a " suture," 

 which nearly passes through the whole scale. 



In the upper part we have the true squamosal, in the lower 

 we see the quadrate. All these separations in the " squamosal " 

 must be considered as atavistic. That they are so without 

 doubt results from Cope's researches on the Pelycosauria of the 

 Permian formation. Cope looks upon these reptiles as the 

 ancestors of the mammals. I have in another place ( c Morphol. 

 Jahrbuch') endeavoured to show that these are somewhat too 

 specialised to answer this hypothesis, but that they are very 

 closely allied to the ancestors of the Mammalia. I give Cope's 1 

 remarks on the quadrate of these interesting forms in his own 

 words : " Although the malar bone is out of place in the speci- 

 men described, examination of the skull of Clepsydrops 

 natalis, where it is preserved in position, shows that this 

 horizontal ramus of the quadrate is nothing more than the 

 zygomatic process of the squamosal bone of the Mammalia 

 forming with the malar bone the zygomatic arch/' 



1 E. D. Cope, " The Relations between the Theromorphous Reptiles and 

 the Monotreme Mammalia," ' Proc. Amer. Assoc. Adv. Sci. (1884, Philadel- 

 phia), vol. 33, p. 473. 



