8 BULLETIN OF THE LABORATORIES 



united and form a quadrate bone making an angle of 25° with the cul- 

 men or upper Hne of the beak, their combined width is .45, and they 

 form the posterior borders of the nares, being united laterally with the 

 maxillaries, anteriorally with the intermaxillary, below with the lachry- 

 mals, and posteriorly with the frontals. The distance from the angle 

 of the mandible to the top of the nasals is .40. Occupying the top 

 of the skull, and apparently restricted to the space between the orbits, 

 are the concciYe fro /ifa/s. The distance between the orbits is about 

 .35. The remainder of the roof of the skull is formed by the con- 

 fluent parietals which occupy a larger area than usual on the top and 

 back of the skull. From above can be seen a small prominence be- 

 hind, which covers the cerebellum, and hence is called the cerebellar 

 prominence. The sides of the triangle are continued backward from 

 the ends of the maxillaries by a slender rod consisting of the quadra- 

 tojugal and \\\*t jiigal which can be studied to advantage when the skull 

 is viewed from the side. In this position the skull is seen to present 

 the outline of two triangles, the smaller of which, forming the beak, is 

 set at an angle of 45° with the other. The cutting edges of the jaw 

 (to?7tia), supported chiefly by the maxillary bones, are slightly curved. 

 The tomia are .80 long. The slender rod passing backward and 

 downward and forming the lower outline of the second triangle is, in 

 the young, composed of two bones, the jugal and quadratojugaL 

 Their combined length is . 54, the posterior articulation being upon the 

 outermost process of the peculiar quadrate bone. This bone is con- 

 sidered the homologue of the little ear bone of mammals, known as 

 the malleus, but in birds has a very important function — that of giving 

 the necessary movability and yet stability to the beak. It is the point 

 of attachment of the two important supports of the facial part of the 

 skull. The form of the quadrate is very irregular, consisting of a 

 body and six processes. The styloid process is the largest and is that 

 which connects the bone with the base of the skull ; it is a flattened 

 vertical pillar with a large articular surface; jutting out anteriorly is the 

 orbital process, about .30 long, which extends into the orbit. Just 

 below the orbital is the pterygoid process of rather small size. The 

 mandiblar end bears two curved processes so situated that the glenoid 

 surfaces oppose the rami from within and behind, while the jaw is com- 

 pletely locked by the large articular process of the mandible. A more 

 complete articulation could scarcely be conceived. The malar pro- 

 cess extends out horizontally and offers an oblique surface to the head 



