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Show 1895.] LORIUS FLAVOPALLIATUS AND PSITTACUS ERITHACUS. 333 below and more so dorsally. The superior margin of the plate in the form of a thin crest convex medianly and bifurcating laterally at its postaxial end (py), at the dorsal margin of the upper flattened part of the hinder margin. In P. erithacus the pygostyle is essentially similar, save that it is triangular rather than a quadrate plate. It would resemble that of L. fiavopalliatus if from the latter all was cut off preaxial to a line passing from the superior extremity of its hinder margin obliquely downwards and forwards to a point between the prezygapophyses. THE RIBS. There are eight or nine dorsal and five ventral ribs on each side (figs. 12 & 14). The Dorsal Bibs. In both species there are two cervical ribs and six or seven true thoracic ribs, whereof five are articulating with the sternum, while one or two are floating ribs. The Cervical Ribs. The first cervical rib is, in both species, long, slender, and devoid of any uncinate process. The tubercular and capitular processes are of about equal length. The second cervical rib is about one-third longer than the first and generally bears an uncinate process (up). If so this is short and does not expand dorso-ventrally at its distal end. The capitular process is somewhat longer than the tubercular one. The Thoracic Ribs. The first thoracic rib is a little longer and stouter than second cervical, and its uncinate process (up) expands distally into a short ventrad and longer dorsad and postaxiad process, so it is much longer dorso-ventrally than antero-posteriorly. The second thoracic rib is again slightly longer, while its uncinate process has a longer dorsal process and a shorter ventral margin. The tuberculum is slightly more distant from the capitulum than iu the first true rib. The third thoracic rib carries a little further the same modifications, save that the uncinate process in L. fiavopalliatus loses entirely the quadrate shape and is subtriangular with a truncated apex. Its distance from the distal end of the rib is also greater. It may still be subquadrate in form in P. erithacus. The fourth thoracic rib has in the last-named species a much smaller and simply shaped uncinate process, which is still further removed from the rib's apex. L. fiavopedliatus differs from P. erithacus in that all the ribs are more slender (relatively as well as absolutely), while the uncinate |