| OCR Text |
Show 376 i DR. ST. GEORGE MIVART ON THE SKELETON OF [May 7, axiad. In L. flavopalliatus it appears, for the most part, above the zygoma. The side wall of the skull seen laterally within the circle of the parts hitherto described presents the following characters:- The anterior portion of the inferior margin (preaxiad of the junction with the palatines) does not ascend preaxiad so sharply in L. flavopalliatus as in P. erithacus, the angle formed by it with the inferior margin of the basis cranii being about 155° instead of 140°. The inferior margin behind the junction with the palatines is rather more concave, and its general trend is nearly in a straight line with the line of the palatine attachment, whereas in P. erithacus these two lines form an angle of about 160°. In both species a prominence-the septal process-is developed at the anterior end of the anteroinferior margin of the cranium (figs. 6, 7, 9, & 10, sp), but it is sharper and more prominent in L. flavopalliatus than in P. erithacus. In both species the side wall of the skull seen within the orbit consists of an antero-inferior septal part (presenting an almost vertical, slightly undulating surface, bounded above and behind by the olfactory and optic foramina) aud a postero-superior surface. The latter inclines outwards and upwards till it reaches the superior margin of the orbit, and presents a smooth surface strongly concave antero-posteriorly and slightly so transversely. It is bounded inferiorly by a transverse ridge (figs. 9 & 10, tr, pp. 383, 384), which runs from a point just external to the small foramina beside the optic foramen, outwards to the postorbital process. Tbis ridge is much more marked and distinct in L. flavopalliatus than in P. erithacus. Near the postero-inferior angle of the septal part is a slightly-marked concavity, which runs forwards from a small rather deep fossa, which is bounded externally by a small process-lateral eustachian process (figs. 6 & 7, le)-which extends forwards to a very slight degree further than the median eustachian process (me), which projects preaxiad beneath the eustachian aperture. Tbis fossa is more marked in L. flavopalliatus than in P. erithacus, but the lateral eustachian process is less sharply prominent. Above this concavity, between it and the optic foramen, is a marked convexity which extends forwards to a little in front of the latter. This convexity is relatively, as well as absolutely, narrower in L. flavopalliatus, and is indeed reduced to a mere rounded ridge passing forwards and slightly upwards to just in front of and beneath the optic foramen. In the superior portion of the septal part there is a concavity just below the large olfactory opening, which is much more marked in P. erithacus. In both species, in front of the large aperture just named, a prominent ridge-the crucial ridge-runs outwards and forwards from about the middle of the front boundary of the olfactory aperture and bounds the preorbital foramen below, ending at the inferior margin of the lachrymal (figs. 9 & 10, cr), and bounds postaxially the concavity last mentioned. The large olfactory aperture at the antero-dorsal part of the septum is subreniform and about twice as long as broad in P. erithacus. In L. flavopalliatus it is more rounded. |
