Bulletin 2s 80 



cies could be more unlike each other than are the skulls of an 

 Hesperornis and an Ostrich— the former being a toothed, Cretace- 

 ous loon, and the latter a recent, toothless, gigantic, struthian 

 land-bird. Their skulls are about as unlike each other as are 

 those of a hummingbird and a kiwi. 



It will be observed that, in getting the outline and restoring 

 the form of the frontal region of Hesperornis ( Fig.i p/\ fr, ), I 

 have followed Marsh, in as much as the outline was obtained by 

 a tracing of Fig. 5, Plate I, as pointed out in a former paragraph 

 of the present article. 



Marsh states, on page 6 of the "Odontornithes," that "the 

 posterior ends of palatines, and the anterior ends of the pterygoids 

 are very imperfectly, or not at all, articulacedwith the basisphen- 

 oid rostrum;" and then, as I have already said, he again points 

 out, on page 7, that the palatines "are long, slender bones, ex- 

 tending from their union with the pterygoids, parallel with the 

 axis of the skull, and joining the premaxillaries." This does not 

 militate against each pterygo-palatine articulation resting upon 

 the base of the sphenoidal rostum, or just beyond its base, as T 

 have shown it in PI. 1 of this article. In fact, if the long axes 

 of the palatines were parallel to the "axis of the skull," as Marsh 

 states was the case, and, as he also states they had a "union with 

 the pterygoids," they must have been placed as I have them in 

 Plate 1, or quite like they are in the loons and other pygopodine 

 birds. From Plate 1 it will be noted, too, that I have restored 

 still another character given us by Marsh ; that is, there are pre- 

 sent "strong 'basipterygoid' processes, arising from the body of 

 the basisphenoid, and not from the rostrum, articulating with 

 facets which are situated nearer the posterior than the anterior 

 end of the inner edges of the pterygoid bones." (P. 6.) 



As to the pterygoids and quadrates themselves, I have restor- 

 ed them as best I could from Marsh's figures and contour lines. 

 He noted that the "upper, or proximal, articular head of the 

 qudrate bone is not divided into two distinct heads," (P. 6.) 

 and this is an important point. There is no question as to his view 

 with respect to the position of the orbital processes of the quad- 

 rate?, for they are given in Fig. 5 of Plate I of the "Odontorni- 



