NO. 2 A MIOCENE LONG-BEAKED PORPOISE KELLOGG 3 



fossae. The maxillary does not entirely sheathe the preorbital angle 

 of the supraorbital process. The hinder margins of the left maxillary 

 are probably imperfect above the temporal fossae. The dorsal sur- 

 face of the left maxillary is depressed opposite the nasals and slightly 

 convex above the supraorbital processes of the frontals. The internal 

 margin of the maxillary, with the exception of the narrow tongue- 

 like portion, which overlaps the frontals on the vertex, is in contact 

 with the premaxillary for practically its entire length. Two foramina, 

 which are connected with the infraorbital canal, are present on each 

 maxillary. The most posterior one of these is situated above the 

 temporal fossa. The other foramen is located at or near the level of 

 the maxillary notch and from it a deep groove extends forward for 

 a distance of at least 20 mm. The outer border of the maxillary at 

 the base of the rostrum is not bent upward as in Eurhinodelphis, but 

 is curved obliquely downward. In correlation with this tapering of 

 the rostrum the maxillary decreases in breadth anteriorly and the 

 sides become more nearly vertical. Anterior to the maxillary notches 

 the premaxillaries are fairly thick and their upper surfaces are con- 

 vex. Their inner margins become closely approximated at a point 

 130 mm. in front of the maxillary notches. The raised outer convex 

 portions of the premaxillaries diverge strongly between this point and 

 the maxillary notches, and constitute the outer border of the more 

 or less flattened internal portions of the premaxillaries. In conse- 

 quence of their tapering, these elevated outer convex surfaces dis- 

 appear in front of the presphenoid. The premaxillaries commence 

 to expand horizontally in front of the nasal bones and attain their 

 maximum width at the level of the anterior walls of the narial 

 passages. Opposite the narial passages there is an oval concavity on 

 each premaxillary. The posterior end of each premaxillary is rela- 

 tively broad, conspicuously thickened, and its dorsal surface is raised 

 to the level of the nasals. The premaxillary foramina are moder- 

 ately large and are situated behind the level of the anterior maxillary 

 foramina. Each of these premaxillary foramina opens into a broad 

 groove, which is continued obliquely backward and outward to a 

 point opposite the narial passages. The internal border of the pre- 

 maxillary, which is somewhat flattened in front of the presphenoid, 

 narrows rapidly and finally disappears anteriorly under the raised 

 convex outer strip. The premaxillaries do not approximate each 

 other as closely in front of the narial passages as in Eurhinodelphis 

 bossi from the Calvert formation of Maryland and hence the mesoros- 

 tral gutter is not roofed over for a distance of 160-175 mm. Proxi- 



