1889.] MR. W. K. PARKER ON STEATORNIS CARIPENSIS. 167 



3 millim. across, and together take up a space of 11 millim., 

 measured across. They then narrow in to 2'5 millmi. and enclose an 

 oval common "middle palatine foramen" or open space 9 millim. 

 long and 6 millim. wide ; the fore end of this space is enclosed by the 

 maxillo-palatines and septum nasi, and is, indeed, the middle notch 

 just spoken of. This space is enclosed beliind by the two palatines, 

 which meet and form an oblique suture 1'5 millim. in extent. 



This second part of the hard palate in this " doubly Desmogna- 

 thous " bird is 8 milhm. across ; behind it the palatines narrow 

 in again, until their lower part is a mere ridge ; but they have curled 

 round now, and formed the low and short " ethmopalatine," or 

 ascending processes, which run under the sphenoidal rostrum for a 

 distance of 6 millim., and are ankylosed together. Behind, the 

 two coalesced palatines are only 3'3 millim. across, where they articu- 

 late with the pterygoid. The outer edge of each palatine is sharp, not 

 limbate ; it is bevelled into an edge from tbe sub-mesial thickest part. 



I have spoken of the prepalatine bars as laths ; tbe middle and 

 hinder part is hke a shaving, coiled obliquely, so that the edges of 

 the two bones meet below, in front, and above, in their hind part. 

 They thus enclose the naso-palatine passages {i.n.), flooring them in 

 front for a short distance, and then roofing them, behind, for three 

 times that extent. The concave opening of these passages behind the 

 short posterior hard palate is eUiptical, 9 milhm. by 4'5 millim. The 

 edge of the two bones enclosing this space is limbate, and corresponds 

 with the inner edge of a grooved palatine bone ; here, there is no 

 groove, but the bone curls upwards at once, to pass into the ascending 

 plate. This is much more primitive, or simple, than what is seen 

 in the Trogons, where they do not unite to form a second part of 

 a hard palate, and have a groove and some angulation of their outer 

 edge. 



Steatornis has two vomers (u.), each .5"5 millim. long and 1 millim. 

 wide ; they are sharp at both ends. The hinder bone has had its 

 distinctness obliterated by ankylosis ; it is probably a " medio- 

 palatiue," like that seen in Caprimulgus, Owls, &c. ; this vome- 

 rine bone, now, forms merely an upper, partial septum between the 

 naso-palatine passages. In a membranous tract in front of the 

 triangular end of the fused vomer there is, at a little distance, 

 a similar bony tract — an " antero-median vomer." The supero- 

 external edge of each palatine, for an extent of 3-5 miUim., is 

 formed by the " mesopterygoid " increment; so that the short 

 trough, 4 millim. in extent, in which the sphenoidal rostrum (pa.s.) 

 lies, is formed by three pairs of bones ; that rostrum runs free of 

 this groove for 7' 5 millim., its projecting point is 3 millim. 

 behind the vertical line of the hinge, and of the notched hind edge 

 of the septum nasi. It is extremely unlike an Owl in this respect, 

 m which bird the hinge-notch is shallow and of great extent ; the 

 rostrum of the sphenoid ends much further backwards in that bird, 

 having no projecting spike in front. The hind part of the sphenoidal 

 rostrum, with its basipterygoid processes (b.pg.), may be described 

 now, because of the relation of the latter to the pterygoids. 



12* 



