234 Annals of the Carnegie Museum. 



upon its under side, and as in the case of that part of the bill, the 

 lower jaw has also a slight dilatation at its distal end. The posterior 

 half of the mandible is acutely V-shaped, its upper and lower ramal 

 borders being rounded and not sharp. The sides increase in vertical 

 depth as we proceed towards the articular ends, and the ramal vacuities 

 do not exist. There is a sizable ramal perforation or foramen however, 

 farther back on either side, near the point where the temporal muscle 

 makes its insertion. Each articular cup is rather small, though its in- 

 ternal process is well-developed and the posterior one even still better. 

 These posterior articular processes are absent in Tantalus but present 

 in A/a/a. Here in Flegadis they each spring from the extreme exter- 

 nal and back part of the articular extremity, and each has to its inner 

 side a concavity which occupies the true posterior aspect of either 

 articular end of the mandible. This part of the bone is pneumatic, 

 but the air-holes are very small, and found further from the apices of 

 the internal articular processes than is usually the case in most birds. 



Seventeen vertebrce are to be found in the cervical region of the 

 spinal column of P/egai/is, before we arrive at that one the ribs of 

 which are joined to the sternum through the articulation of hrema- 

 pophyses or costal ribs. This is the eighteenth vertebra, and it together 

 with the nineteenth, twentieth and twenty-first are solidly ahchylosed 

 together so as to form one bone, such as we find among the typical gal- 

 linaceous fowls. The twenty-second vertebra is free and stands be- 

 tween this compound dorsal piece and the sacrum of the pelvis. This 

 latter has fourteen more vertebrae in it, they being fused together as in 

 the sacra of all ordinary birds. In the skeleton of the tail we find five 

 vertebrae, and to these is to be added the pygostyle. Thus it will be 

 seen that this Ibis has forty-one vertebrce in the skeleton of its spinal 

 column, plus a pygostyle, which is probably composed of several others. 



There is a tiny pair of free ribs, of the most elementary character, 

 on the sixteenth vertebra ; the free pair of the seventeenth are rather 

 long and slender, and are possessed of uncinate processes. Then 

 follow six pairs of tn/e 7-ibs, all of which unite below with the sternum 

 by means of connecting costal ribs. The last pair is a ])elvic pair 

 and they lack unciform processes. All the rest have these, though 

 they become progressively smaller as we pass from the ribs of the 

 eighteenth vertebra to those of the twenty-second. These unciform 

 processes anchylose with the several ribs to which each one belongs. 

 These ribs are narrow, very thin and slender, and from first to last 



