| OCR Text |
Show 380 DR. ST. GEORGE MIVART ON THE SKELETON OF [May 7, the palatines. Into the posterior angle of this triangular space the sphenotic process (sph) is seen to project in P. erithacus but hardly in L. fiavopedliatus. The zygoma arches outwards most at a little behind its anteroposterior middle in both species. The preorbital prominence also projects outwards beyond the anterior half of the zygoma, and between the latter and the outer margin of that process the lachrymal is seen extending backwards and slightly outwards to about the hinder end of the anterior three-fourths of the zygoma in L. flavopalliatus, and to about the hinder end of its first third in P. erithacus. The quadrate (q) in the last-named species presents, thus viewed, a roughly triangular surface, with one margin mesiad (postaxiad from the attachment of tbe pterygoid), another externad and postaxiad, and the third (between the attachments of the zygoma and pterygoid) preaxiad and externad. The last is strongly concave, the second very slightly so, while the first is nearly straight and forms the inner margin of the elongated convex articular surface for the long articular concavity of the mandible. The quadrate of L. flavopalliatus only differs in that the secoud margin is relatively as well as absolutely shorter, the quadrate (as before mentioned) extending so much less backwards behind its attachment to the zygoma. The angle formed by the first and second margins is also much more obtuse than in P. erithacus. The hindmost boundary of the ventral aspect of the cranium is, in both species, formed by the lambdoidal ridge. In front of this is the occipital region, bounded anteriorly by the occipital condyle and two lines proceeding thence to the two paroccipital processes. Medianly there is visible a median prominence (which is one running dorsad from the middle of the dorsal margin of the foramen magnum) and a depression on either side of it. The prominence is rather more marked in L. flavopalliatus than in P. erithacus. Tbe deep cleft between the quadrate and the end of the paroccipital process is absolutely as well as relatively greater in L. flavopalliatus than in P. erithacus, while the quadrate does not extend backwards so far, and is relatively much more distant from the hinder end of the paroccipital process. Just in front of the condyle is a small fossa which is very much more marked in L. flavopalliatus. In front of this again, in the same species, is a transverse zigzag ridge which bounds postaxially the basi-temporal shield (bts). This ridge has the shape of the letter M with extremely wide angles, the median angle being postaxiad and forming the antero-inferior boundary of the small pre-condyloid fossa just mentioned. Each lateral end of the ridge bounds the jugular foramen anteriorly-the vagal foramen opening just above it-and joins a ridge bounding laterally (on the same side) the basi-temporal shield (bts). In P. erithacus this transverse ridge is very indistinct and not M-like, and presents four small postaxiad prominences on about |
