12 SHTJFELDT — OSTEOLOGY OF THE CUCKOOS. [Jan. 4, 



bar. The horizontally expanded end alluded to is quite ample and 

 may be perforated by numerous foramina. Its maxillo-palatine 

 development will be described when speaking of the under side of 

 the skull. 



The remainder of the quadrato-jugal bar becomes gradually 

 larger and club-shaped as it nears the quadrate bone, to rather 

 abruptly turn inward as it reaches it, and is inserted in a vertical 

 notch in the usual apophysis of that element, which projects directly 

 outward to meet it (PI. I, Fig. 2). 



With respect to the quadrate, we find that its orbital process is 

 very broad and flat, being at the same time very short. The body 

 of the bone is also broad, while its mastoidal apophysis is twisted 

 in a way common to many other birds, and supports at its summit 

 two articular heads with a distinct valley between them. At the 

 inferior aspect of the mandibular foot there are two condyles for 

 articulation with the lower jaw. The inner and smaller of these 

 is hemi-ellipsoidal in form, with its major axis in the same straight 

 line that constitutes the longitudinal axis of the corresponding 

 pterygoid. If this axis be produced the other way, it is found to be 

 at right angles to the long axis of the other and larger facet of the 

 mandibular foot of the quadrate. Rather a broad notch separates 

 these two condyles from each other. 



The quadrate is a thoroughly pneumatic bone, and a large fora- 

 men is always found upon its posterior aspect half way between the 

 mastoidal head and the mandibular foot. 



Both the sphenotic and mastoid processes are well developed in 

 this bird ; they are of about an equal size, the first being directed 

 downward, and the last downward and forward. Between them, 

 and carried well to the rear, is a sharply defined and rather deep 

 crotaphyte fossa. It is separated from a like depression of the 

 opposite side by an interval of one and a half centimetres. These 

 crotaphyte fossae are fully as well marked in Geococcyx as they are 

 in many of the Laridce, and better than they are in some members 

 of that group of birds, better, for instance, than they are in Larus 

 Philadelphia. 



Owing to the great breadth of the frontals, the orbit is completely 

 sheltered above by an arching roof, the outer periphery of which is 

 concave inward and bounded by a sharp edge. This orbital vault 

 usually shows posteriorly a few perforating foramina. The rostrum 

 of the sphenoid is pneumatic and rounded for its entire length 



