. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. THE CRANIAL MORPHOLOGY OF THRINAXODON LIORHINUS SEELEY 369 directed flange of the lateral wall of the sella turcica which lies in the dorsal surface of the basisphenoid (Figs 6A, 16A, 21C, BS, WST, Fvi). Olson's (1944) figure is therefore more closely comparable with the structure as determined in the present investigation than Parrington's (1946) figure in which the foramen lies entirely within the antero-ventral process. Sectioning shows that the foramen lies behind the sella turcica and the unossi
. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. THE CRANIAL MORPHOLOGY OF THRINAXODON LIORHINUS SEELEY 369 directed flange of the lateral wall of the sella turcica which lies in the dorsal surface of the basisphenoid (Figs 6A, 16A, 21C, BS, WST, Fvi). Olson's (1944) figure is therefore more closely comparable with the structure as determined in the present investigation than Parrington's (1946) figure in which the foramen lies entirely within the antero-ventral process. Sectioning shows that the foramen lies behind the sella turcica and the unossified zone. The foramen for the facial nerve (Figs 24A, 27, 28, Fvii) is quite distinct immediately below and behind the prootic incisure (posterior wall of the trigeminal foramen) from which it is separated by the prefacial commissure. The ramus ophthalmicus profundus of the trigeminal nerve probably ran forward along the medial surface of the lower third of the epipterygoid from the Gasserian ganglion lying just within the trigeminal foramen. Its possible course is indicated by a slight though definite groove on the medial surface of the epipterygoid just above the level of the antero-ventral process of this bone. On emerging from the braincase through the lower end of the foramen lacerum anterium (Fig. 6A, FLA), the ramus ophthalmicus profundus would have been immediately above the anterior ventral part of the epipterygoid (Fig. 18, CROPv) which is in contact anteriorly with the pterygoid, and more posteriorly with the basisphenoid (Fig. 18B, BPTPL).. Fig. 25. A. Antero-ventral view of posterior part of enlarged wax reproduction of serially sectioned skull to show contacts of stapes and quadrate. Note retroarticular process of articu- lar. Bl, 2, 3, 4. Lateral, ventral, anterior and medial views of right stapes. Note positions of anterior, dorsal and posterior planes in the different views, x 2, Please note that these images are extracted from scanned page images that may
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectnaturalhistory, booky
