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 judice. 



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

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

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



a-M. 



a=M. 



A series of diagiams to illustrate the metamorphoses of the palato-pterygoid 

 arch in Birds, Crocodiles, and in Man. 



P=pterjgoid ; C=cartilage; (2=the quadrate. In Man the malleus is the 

 equiyalent of the quadrate, and is represented thus : Q=M. M.C., 

 Meckel's cartilage ; P. G. processus 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 separated 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 M'hich 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 my 

 view previously expressed, that the parasphenoid of the ainphibian 

 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, Strufhio camelus, to show the 



lingulfB, i/. A.S, Alisphenoid; .B.-S, basisjihenoid; i'^.ilf, foramen 

 magnum. 



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



P.P, The author's postpalatines ; P.N, posterior nares ; E, opening 

 of Eustachian lube. 



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



