Bulletin 25 76 



such an outline may be filled subsequently. To obtain this, I 

 made a careful tracing on transfer paper of Marsh's Fig. 5 of 

 Plate I of the "Odontornithes," which represents, natural size, the 

 ''skull" of Hesperornis regalis, seen directly from above. With the 

 mid-longitudinal axis of the cranium parallel to the plane upon 

 which the latter rests ; the point of view from above being at the pro- 

 per distance to a\ oid the distortion caused by being too near, and 

 in a line perpendicular to the aforesaid plane, crossing at its 

 middle point the transverse diameter of the cranium situated at 

 an equal distance between its two extremitie- — is presumably the 

 view given in Fig. 5 of Plate I ; so that, if the cranium w T ere 

 turned completely over and placed in the same position just des- 

 cribed, the outlines seen would be identical, provided we regarded 

 the cranium when thus placed from the same viewpoint. There- 

 fore, the tracing I made of the outline of the superior view shown 

 in Fig. 5, would be equally accurate for the corresponding inferi- 

 or ventral view of this cranium, and likewise be of natural size. 



Fig. 1 of Plate II of the "Odontornithes" presents the in- 

 ferior surface of the premaxillary and maxillary bones, with a 

 tooth ( t ) in the groove of the latter on the left side. This draw- 

 ing I take to be an accurate one, for the reason that all of its out- 

 lines agree with those of the same parts shown in Fig. 5, Plate I 

 for the superior view; consequently, as far as it would can-y, I used 

 it in my restoration, which latter illustrates the present article. 



The cultrate margins of the superior osseous mandible (pmx) 

 were formed by the premaxillary bone, and, upon either side, 

 they extended backwards for a distance of 8.9 cms., terminating at 

 the maxillo-premaxillary suture, which is distinctly shown in the 

 accompanying Plate. At this point the superior osseous man- 

 dible has a transverse diameter of 1.75 cms.; and at a distance of 

 one centimeter upon either side, posterior to it, the grooves for 

 the teeth commenced. Each of these grooves measured antero- 

 posteriorly, 5.2 cms., and had implanted in them, in the manner 

 described by Marsh, fourteen teeth. Either groove is nearly 

 straight, and lies entirely in the outer inferior part of the maxil- 

 lary bone on either side. The free apices of these teeth are directed 

 downwards and backwards, and their description has been given 



