1885.] 



OF THE HUMAN SPHENOID BONE. 



587 



as I have been able to look into the question, is that they do, but 

 until my material is more abundant the question, with me, remains 

 sub juflice. 



Fig. 4 is an attempt to represent in a graphic manner the meta- 

 morphosis of the palato-pterviioid bar in a Bird, in a Crocodile, 

 and in Man, so as to explain how it comes about that in a Bird the 



Fig. 4. 



p 





a=M. 



Ci=M. 



A series of diagiams to illustrate the metamurpliuses ul' the palato-pterygoid 



arch in Birds, Crocodiles, and in Man. 

 P=pterjgoid; C=:cartilage; (3 = the quadrate. In Man the malleus is the 

 equiTalent of the quadrate, and is represented thus : Q=zM. 31. C, 

 Meckel's cartilage ; P. G. jDrocessus gracilis. 

 The upper row of figures represent the cartilaginous bars, arranged in order 

 from left to right — Bird, Crocodile, and Man. The lower row represent the 

 adult condition. 



true pterygoids rest on the quadrate, but in the Crocodile and in Man 

 the true pterygoids are se])arated by a piece of" cartilage. 



Lastly, in a preceding paper I endeavoured to dispose of the blade 

 of the famous parasphenoid. On the present occasion I try to show 

 that the view which would regard these basitemporals (postpalatines) 

 as the homologues of the lateral portions of the Frog's parasphenoid 

 is against the weight of evidence. The investigation supports ray 

 view previously expressed, that the parasphenoid of the amphibian 

 skull is represented in the highest mammals by the vomer, and by that 

 bone alone. 



EXPLANATION OF PLATE XXXV. 



Fig. 1. View of the base of the skull of a Chick at end of second week. P.P, 

 Postpalatine (basi-temporals of Parker). 



2. Under view of the skull of a Frog, to show the general appearance and 



relation of the so-called parasphenoid, P. The lateral portions are 

 marked L. 



3. The sella turcica of a yoimg Ostrich, Sfruthio camelus, to show the 



lingulfe, i. A.8, Ali.^phenoid ; .B..S', basisphenoid ; i^.xl/, foramen 

 magnum. 



4. The hard palate of a Crocodile, to show the so-called pterygoid bones. 



P.P, The author's postpalatines ; P.iV, posterior nares ; i?, opening 

 of Eustachian tube. 



(Figs. ], 2, and 4 after Parker.) 



