THE QUADRATE BONE IN BIRDS, 5 
Heron. The position of the quadrato-jugal cup is more normal. The posterior 
part of the mandibular articulation is produced on its outer side with a special 
grooved surface, which in the Heron is very slightly indicated, and in Ibis is 
absent: the anterior condyle passes gradually into a large accessory trochlear 
surface. 
In Ibis, the capitula are somewhat less separate than in the other two. The 
angle between the shaft of the bone and its anterior process is very obtuse. The 
Fig. 7. Bis FALCINELLUS. 
pterygoid condyle is not so far forward. The posterior portion of the mandibular 
articulation is normal ; the accessory trochlea on the anterior part is very distinct. 
It will be observed that these three forms agree closely with one another, and 
all resemble Phcenicopterus. But Ibis is the most like Phcenicopterus in the 
characters of its mandibular articulation, its accessory trochlea, the obtuse angle of 
its anterior process, and the position of its pterygoid condyle. Indeed, the quadrate 
of the Ibis resembles that of the Flamingo fully more than it does that of either of 
its Pelargomorph allies. 
IV.—DysroroMoRPHz. 
The three types of Dysporomorphe that we have examined—the Pelican, 
Gannet, and Cormorant—show, in several respects, a quite unexpected amount of 
dissimilarity. 
In the Pelican, the two capitula are well defined. The anterior process is 
Fig. 8. PELECANUS ONOCROTALUS. 
of moderate size, and pointed. The quadrato-jugal cup is imperfect posteriorly, 
forming merely a crescentic hollow above the posterior portion of the mandibular 
