ShUFKI.DI- : OSTKOLOOY OK THK H I'.KODIONES. 'J,'}.'? 



in my collection exhibits this condition, and it agrees with what we 

 find in Tantalus and its palatine bones. In fact, as different at first 

 sight the bones at the base of the skull appear to be in Tantalus and 

 these ll)ises, they are fundamentally the same in character. The 

 nia.xillo-/>ala tines are large, spongy bones, completely overlaid with a 

 thii. coating of compact tissue. Posteriorly, they e.xtend far backwards 

 and are here well-separated from each other, the entire interpalatine 

 space and the vomer standing between them. In this region too, they 

 mount w^ell up into the rhinal chamber occupying much of its room. 



Between the maxillaries and immediately in front of the apex of the 

 vomer their behavior is very different. They here cross the median 

 space to completely fuse with each other, and that for a distance for at 

 least a centimeter in front of the vomerine spine. This desmognathous 

 condition is not quite as complete, or rather quite as extensive, as it 

 is in Tantalus for example, because in front of those fused maxillo- 

 palatines in the Ibis we again meet with another open vacuity in the 

 middle line, which may be a centimeter or more in length. It usually 

 extends as far forwards to a point nearly opposite the anterior termi- 

 nations of the external narial apertures, which, of course, are above it. 

 We may add here, what perhaps should have been said in another place 

 above, that we find a small foramen al)ove either pars plana, for the 

 passage of the nasal nerve, and the supero-anterior part of one of those 

 mesethmoidal wings is turned forwards in a peculiar manner, so as to 

 form between it and the mesial ethmoidal plate proper a deej) fossa, 

 open in front and below. Plegadis has the osseous circlet of sclerotal 

 plates in the eyes complete as in other birds, but the individual pieces 

 are each very small and overlap their fellows all round for at least a 

 third of their surface, the arrangement gives a large pupillary ajierture, 

 and the posterior plates are but slightly larger than the anterior ones. 

 Ear bones have been lost in all my present specimens, as have those 

 of the hyoidian apparatus. 



Coming to the n/and/l'le we find it decurved in a manner to cor- 

 res[)ond to the upper bill. This curvature is general from one end to 

 the other. The anterior ramal symphysis is very extensive, extending 

 back for nearly or (piite half the length of the bone. Below, it is 

 deeply grooved in the middle line from the apex to where the symphysial 

 part terminates posteriorly. This grooving is also seen upon the 

 superior aspect, but much more fully marked. A similiar longitudinal 

 L,Toove also occurs down the entire middle line of the superior mandible 



