166 MR. W. K. PARKER ON STEATORNIS CARIPENSIS. [Apr. 2, 



The culmen of the rostrum in Steatornis is subacute (Plate 

 XVII. fig. 2); its dorsal outline forms an almost perfect quadrant, 

 it is somewhat wavy, and drops suddenly near the hinge, which is 

 straight across the skull, and is perfect. The nostrils (figs. 1, 2, e.n.) 

 are in front of the middle of the rostrum, reniform, oblique, and 

 6 millim. long ; a small alinasal valve, covered by the ossified roof, 

 forms the " liilus " of the kidney-shaped opening. 



These ossified roof-cartilages {al.n.) are full of vascular borings, 

 which give them a different appearance to the nasals and premax- 

 illaries («., px.). But the fusion (ankylosis) of these parts is 

 perfect, and so also is that of the ossified septum nasi, with the 

 surrounding bones. That wall has in its middle a large pyri- 

 form fenestra, 4 millim. long and 3 millim. deep, a structure 

 more frequent in Aquatic and Grallatorial birds than in the higher 

 Arboreal types. This is one of its aberrant characters ; the inferior 

 turbinal (right and left) remains unossified. Under the bulging 

 alinasal tracts there is a gently concave, wide sulcus, which ends in 

 an open space between the rostrum and the ectoethmoid (pats 

 plana). At this part of the skull the angles of tlie maxillaries 

 (figs. 2, 3, mx.) are 20 millim. apart ; and close here, in the hollow 

 behind the descending cms of the nasal, the projecting maxillo- 

 palatiue (figs. 1-3, mx.p.) is seen, right and left. 



This lateral rostro-cranial space should be largely filled in by 

 the lacrymal (fig. 1, /.), which is so constantly large with a con- 

 siderable frontal suture, and a broad supraorbital tract, in the 

 Cuculines generally. Here, however, in Steatornis, it is very small, 

 and is ankylosed to the nasal, forming a small projection, 3 millim. 

 in extent, to the postero-superior edge of the rostrum. This con- 

 dition of things is very common in such Passeres as possess a small 

 lacrymal ; in the Corvidse, Laniidse, and some others it is pupi- 

 form and free. 



In the Woodpecker (Gecinus viridis), and in that marvellously 

 aberrant Fowl, Ojjisthocomics, the same thing is seen ; the lacrymal 

 being very small, and ardvylosed to the nasal. 



The margin of the rostrum is cultrate, and the dentary edge is 

 separated by a groove from the palatine face of this region ; the 

 middle is gently ridged, and this ridge passes into the ossified 

 septum nasi {s.n.), which in its fore half is marked off by a right and 

 left chink. In its hinder half it is higher than, but ankylosed to, 

 the maxillo-palatines (mx.p.), which swell downwards, right and left, 

 and have a notched hinder margin. Between these parts there is 

 another sharp notch, filled in, in front, by the bony nasal septum. 

 The outer notches as well as the inner are in front of the maxillary 

 angles, and the whole posterior palatal margin of the rostrum is 

 thus strongly serrate. 



The maxillo-palatines (fig. 3, mx.p.) are only moderately high and 

 spongy ; under their thickest part the prepalatine laths (pa.) pass 

 forward and are ankylosed to them. The fibrous fore part of the 

 prepalatiues reaches as far forwards as the middle of the septum 

 nasi ; where they escape from under the maxillo-palatines they are 



