BIIIANO TILL K. SV. VET.-AKAI). IIANDL. BAND 25. AFD. IV. N:0 5. 5 



minute or absent, there being no traces of them in any of 

 the numerous specimens. The binder supramaxilla (fig. 3) is 

 longer than deep, displaying a considerable facette for the 

 overlap of the maxilla; its antero-snperior angle is slightly 

 thickened and prodnced into a slender point. The anterior 

 supramaxilla must, by inference, have been elongate- triangulär 

 in shape, but this element is probably the bone shown of 

 the natural size in fig. 4. The dentary bone (figs. 5, 6) is 

 remarkably stout and deep, with a slightly convex lower 

 börder, and a considerable styliform backward extension 

 beneath the articulo-angular element (a). Its symphysial end {c) 

 is bluntly pointed, but the oral börder rapidly rises, and the 

 very short gape of the mouth is bounded behind by a large 

 and broad, truncated »coronoid» process (&), which bears a thin, 

 triangulär, posterior wing. The precise fbrm of the articulo- 

 angular is unknown, but remains of tliis bone in no. A sug- 

 gest that throughout its extent it was as deep as the deepest 

 part of the dentary, and did not extend far behind the 

 postero-inferior process of the latter. 



Above the maxilla, tliere must have been suhorhital 

 cJicck-plaies, and one of these preserved in no. C is interesting. ■ 

 This specimen (fig. 7) may be im])erfect, but it clearly shows 

 that the sensory canal which traverses its upper margin, 

 exhilnts a few straight branches radiating downwards half 

 the depth of the bone. 



The operculum (fig. 8) is trapezoidal in shape, its upper 

 börder the shortest, its anterior and lower borders a])proxi- 

 mately eijual in length. All its margins are straight except 

 the hinder one, which is slightly convex. Its point of sus- 

 pension (a) is high, and the sutural line between this bone and 

 the suboperculum must have sloped sharply upwards behind. 

 Its outer face is smooth, marked only by a few of the concentric 

 lines of growth. The stihopcrcnJum (fig. 9) is somewhat more 

 than twice as broad as deep, but a little variable in pro- 

 portions, with a very slight ascending process in front. 

 There is one small sinuosity in its lower margin. Like the 

 operculum, it is marked only by a few of the concentric 

 lines of growth. The p>reoperculum (fig. 10), well sliown in 

 many specimens, but especially well displayed from the inner 

 asj)ect in no Gr, is sharply bent at its angle, and has the 

 lower limb nearly as largo as the ascending limb. It tapers 



