230 Annals of thf Carnegie Museum. 



ated slits, and the premaxillary processes of the nasal bones are defined. 



The long, curlew-like superior mandible is very much decurved, and 

 the culmen is rounded off. It is roughened towards the tip as in 

 certain snipes, and, as in them, somewhat transversely dilated distally. 

 The extreme apex is bluntly rounded. On the posterior aspect in 

 P/('xm:/is we find the sui)raoccipital prominence very conspicuous, and 

 upon either side of it, a large, subelliptical foramen. These two 

 characters are not so strong in Guara, where the foramina are rela- 

 tively, as well as actually, smaller and more elongate. In this genus, 

 however, an "occipital ridge" is pretty well marked, and it is not 

 so evident in P/ej^d //s. The crotophyte fossai are, mesially, well 

 separated. 



Upon lateral view, we notice that the anterior end of the narial 

 slit in the beak is extended forwards as a narrow split aperture more 

 than half way towards the extremity, as it is in the Curlew (^Numeniiis). 

 Ibises, however, have the separated premaxillary limbs thus formed, 

 far more rigid than they are in the Curlews. This is due to the fact 

 that the maxillary fork of the premaxillary is deeper and stouter in 

 the Ibises, and it is more firmly held in place by the enlarged and 

 united maxillo-palatines within. Plegadis has a very slender and 

 straight zygoma, with its maxillary end completely fused with, and 

 much hidden by the bones surrounding it. The free bar of the 

 nasal bone, or that portion passing between the frontal region and the 

 maxillary process of the premaxillary, is straight and flattened. 



A lacrytnal makes a very extensive and close union with the edge 

 of the frontal bone and nasal. Actual anchylosis, however, does not 

 take i)lace along the line of the suture. Its superior portion is sub- 

 horizontal in position and from this part it sends inwards a distinct 

 process towards the rhinal chamber ; and downwards a broader and 

 antero-posteriorly flattened process towards the maxillary. This latter 

 bone it reaches by the intervention of a well-developed osseous rodlet 

 representing an os uncinatiDii. This descending process of the lacrymal 

 also sends directly inwards a small process that touches the tip of a 

 similar one sent outwards on the part of the small quadrate /<;?;■.>- //(i-z/a. 

 The anterior wall of the brain-case is entire, as is also for the most 

 part the interorbital septum. The foramen for the exit of the first 

 pair of nerves is nevertheless much cut awa^ ; while on the other hand 

 the foramen rotundum, and the smaller nervous foramen to its outer side, 

 are not so very much larger than is required to pass the nerves they 



