| OCR Text |
Show 1870.] DR. J. MURIE ON SAIGA TARTARICA. 463 The squamous portion of the temporal bone (Seq) has a low smooth-surfaced longish elliptical figure, its anterior angle abutting against the alisphenoid. The zygoma arises by a thin broadish horizontal piece, scooped out at its root above, and perforated by a wide foramen ; and as the bone arches forward to unite with and overlie the jugal, it thickens. The glenoid (gl) or articular surface is pretty convex, and, with a shallow postglenoid sulcus, much narrower than in Antelopes generally; and the large postglenoid foramen still further reduces it. The articular eminence or tubercle is small, but well marked. The auditory meatus (au) has a moderate diameter, and is directed very gently upwards and forwards. The styloid process or plate is short; and the fossa for the attachment of the articular portion of the stylohyal is likewise as in Sheep, small. The mastoidal eminence is not nearly so full and prominent as in most Bovidae ; it nevertheless rises in a pronounced roughened ridge, which, however, is scooped out towards the root of the paramastoid. The tympanic bulla (Ty) is rather well developed, and moderately inflated. The paramastoid process (Pmd.), one inch long, descends almost vertically ; seen from behind, it is laterally compressed, with a slight outward obliquity of the posterior border ; but from the side, is flat and V-shaped, and partially rests against the tympanic. A wide, deep excavation intervenes between the paramastoid and the condyle ; and this cavity narrows to a curved fissure betwixt the tympanic and basioccipital bones. A narrow strip of the supraoccipital (So) forms the hinder portion of the top of the skull. Its lambdoidal suture, in the Society's male specimen, runs transversely with a double forwardly convex curve, this being straighter in the Hunterian skeleton. The superior curved line describes a full arch, is rough, and only moderately prominent; an inferior curved line, less marked, is well nigh obsolete. An external occipital protuberance is but very partially denoted, although the spine is broad and well developed. The hollows to which the long muscles of the neck and the liga-mentum nuchae cranially fix themselves are distinctly and separately impressed, giving a rugose surface to the occiput, which is altogether broadly arched. The supraoccipital facies is neither so bulging as in Antelopes and Goats, nor so perpendicularly scooped as in Deer It agrees more, therefore, with Sheep, but in the male Saiga has not such strong ridges and concavities as in the thicker-necked Ram. The articular condyles of the exoccipital (Eo) have each a transverse ungulate figure, which, convex from before backwards and laterali)-, is yet less prominent or posteriorly sustained than in the Antelopes, coinciding rather with Sheep and Deer. The nearly circular or slightly transversely oval* foramen magnum pertains to Ovis in its moderate diameters. Divergently forwards from the inferior root of the condyles, two transversely ridged, large-sized eminences stand out (p. t.), these in disposition and breadth following the type of * Decidedly ovoid in the Cambridge female skidl examined by me. |
