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Show 1885.] OF THE HUMAN SPHENOID BONE. 587 as I have been able to look into the question, is that they do, but until m y material is more abundant the question, with me, remains sub judice. Fig. 4 is an attempt to represent in a graphic manner the metamorphosis of the palato-pterygoid 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. A series of diagrams to illustrate the metamorphoses of the palato-pterygoid arch in Birds, Crocodiles, and in Man. P=pterygoid; C=cartilage; Q=the quadrate. In M a n the malleus is the equivalent 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 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 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 my 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 young Ostrich, Struthio camelus, to show the linguke, L. A.S, Alisphenoid; i?.tf, basisphenoid; F.M, 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 tube. (Figs. 1, 2, and 4 after Parker.) |