178 MR. W. K. PARKER ON THE OSTEOLOGY 



pterygoid process of the basisphenoid. The " Struthionidaj," as we shall see, offer the 

 very opposite of this condition, this anterior pterygoid process being in them placed so far 

 backwards as to receive only the end of the pterygoid, which is jammed in between that 

 long peduncle and the os quadratum (PI. XLII. fig. 1, pg.). We shall soon see how this 

 bears upon the affinities of the Syrrhaptes and the Tinamou. 



The large, inflated, shell-like posterior pterygoid processes of the Hemipodius (Pis. 

 XXXIV. & XXXV.) are more like those of Vanellus even than of Columba ; least of all 

 are they like the same parts in the Quail. So wide a " trumpet" do they form, with 

 the help of the basitemporals and anterior tympanies below, that the Eustachian tubes 

 are direct continuations of the cavity of the ear-drum. Their anterior termination, 

 however, is very small, as they contract somewhat rapidly, and then open into one 

 common vestibule, above the lip of the coalesced basitemporals, and beneath the 

 scooped proximal portion of the rostrum of the basisphenoid (Pis. XXXIV. & XXXV. 

 fig. 1). 



The rostrum of the Hemipodius (b.s.) is short, thick, and cellular ; anteriorly it is 

 sheathed by the broad, short vomer ; then three-fifths more of it is embraced by the 

 ascending plates of the palatines and pterygoids. It is then free for some distance 

 — two-fifths, or nearly, of the posterior part. No trace is left of its suture with the 

 base of the ethmoid. The presphenoid is high up out of the way of the basisphenoid 

 (p.s. & b.s.). The " sella turcica " is very neat and very deep ; and the carotid fora- 

 mina, at its narrow, backwardly placed fundus, large. The anterior clinoid processes 

 are wide apart and sharp: the posterior pair have coalesced (as is usual), and form a 

 thick, forwardly inclining wall, against which the base of the brain leans. Two bosses, 

 near together, show, in the adult, that the posterior clinoids were ossified from each 

 side, and that they thickened before they met. The alisphenoids of the Hemipodius 

 (a.s.) are well ossified : they, with the imperfect orbital plates of the frontals and the 

 exogenous orbital alse of the presphenoid, wall-iu the brain antero-inferiorly. There 

 are two distinct eminences for muscular attachment on each alisphenoid ; these 

 represent the external pterygoid plate of Mammals. The alee of the presphenoidal 

 ossification have coalesced with the frontals and alisphenoids at their point of junction. 

 A small, flat, narrow process descends from the presphenoid towards the junction-line 

 of the high part of the base of the rostrum with the postero-inferior portion of the 

 ethmoid. The presphenoid, however, interdigitates by sharp sutural teeth with the 

 postero-superior process of the ethmoid (^^.e.). This latter process is longer than the 

 one that runs forwards to meet it. Not half the interorbital septum is ossified ; for, 

 although the ethmoid fills up some space below, it is cut away in a concave manner 

 between its two backward processes — a large, oval, membranous space having been 

 left by the feeble growth of what was, in an early state of the embryo, a perfect 

 cartilaginous septum. 



Between the postero-superior process of the ethmoid of Hemipodius, and the anterior 



