1895.] LORIUS FLATOPALLIATUS AND PSITTACUS EUITHACUS. 379 



prosopium and laterally, and also postaxially, by the palatines. 

 The anterior and larger portion ot' the roof of this spat-e is formed 

 by the postpalatal ventral surface of the prosopium ; behind the 

 hinder margin of this surface it is roofed by the basis cranli. 



This part of the ventral surface of the cranium shows in 

 L. jiavojjalUatus a median, triangular raised surface narrowing 

 backwards and traversed antero-posteriorly by a slightly marked 

 ridge. Externally this surface is a groove widening backwards, 

 with a perforation at its hinder end for the olfactory nerve. Post- 

 axially each of these fossae is limited by a transverse ridge — the 

 crucial ridge (tigs. 9 & 10, cr). Beneath the anterior part of the 

 fossa a sharp uncinate process projects inwards, and, at its apex, 

 somewhat backwards. 



In. L. jlavopalliatus the Aovs^ T^ovi'ion of each palatine is bent 

 mesiad to meet the corresponding part of the other palatine much 

 more sharply than in P. erithacus, go that when the basis cranii 

 is looked at these bent-in portions of the two palatines present a 

 considerable extent of flattened surface almost equalling that of 

 the hinder margin of the bony palate between the two palatines. 

 Moreover, each bent-in part forms internally almost a right angle 

 with the vertical main portion of the bone, while externally (or dor- 

 sally) the angle is yet moi-e marked. In P. erithacus each palatine 

 gently curves to meet its fellow, so that there is hardly any ventral 

 fattened surface, while internally the median part forms a very 

 obtuse angle with the vertical main portion of the bone, though 

 externally (or dorsally) the angle is very marked and the dorsal 

 surface is flattened and transversely concave. Thus the inner and 

 outer surfaces of the palatine correspond in neither species. 



From the inner end of the anterior margin of each palatine an 

 anterior palatine process ^ extends forwards beside its fellow of the 

 other palatine. These are less marked in P. eriihacus, and they are 

 not side by side but diverge more forwards, so leaving a greater 

 gap between them. On the other hand, this species has (as before 

 mentioned) long posterior palatine processes which are wanting in 

 L. jlavopalliatus. In the latter there are two postaxial processes, 

 one on side of the posterior end of the mid-junction of the palatines, 

 so that the postaxial margin of the two conjoined palatines presents 

 three concavities instead of only one as in P. erithacus, though a 

 delicate styliform process extends backwards from the ventral and 

 inner surface of each palatine to beyond its postaxial margin. 



In both species the pterygoids {pt) diverge from the middle of 

 the hinder margin of the palatines and the rostrum of the basis 

 cranii, with which latter, however, they do not articulate. 



The palatine, the pterygoid, and the zygoma of each side bound 

 a triangular space vv'herein is seen the roof of the orbit. The 

 great olfactory opening is hidden (in this view) by the palatines. 

 In the front of each of these triangular spaces is seen the junction 

 of the prosopium with the cranium and the part behind it (just 

 described), only the crucial ridge is almost entirely concealed by 

 ^ See above, p. 375, the first three lines. 



