ART. 26 REMAINS OF FOSSIL PORPOISES KELLOGG 13 



A slight bowed effect is imparted to the rostrum by the curvature 

 of the latero-ventral margin of the maxilla and by the combination 

 of two other features, namely, the upvrard curvature of the anterior 

 end and proximally by the gradual slope of the dorsal surface to 

 the vertex of the skull. From a lateral view the maxilla appears 

 to be deepest near the distal end of the proximal one-third of the 

 rostrum, but this is due to the curvature of its outer and lower 

 margin. At this point the maxilla is deeper than the premaxilla. 

 Farther forward they are almost equal in depth. Inasmuch as 

 some confusion may arise from differences in interpretation atten- 

 tion should again be directed to the absence in any of the skulls 

 from the Calvert cliffs of any indication of a suture between the 

 maxilla and premaxilla in the position shown by Abel. A shallow, 

 ill-defined groove, however, is present on most of the skulls. If 

 this groove really marked a suture, then the maxilla would taper 

 and end in a sharp point while the premaxilla would increase in 

 depth and finall}^ comprise the extremity of the rostrum. 



The orbit is moderately convex, the outer margin of the supra- 

 orbital process being thick and the superimposed j^late of the maxilla 

 thin and shelving. The preorbital portion of the supraorbital proc- 

 ess is rounded, while the postorbital portion is compressed dorso- 

 ventrally. The lachrymal is closely appressed to the anterior face 

 of the supraorbital process and is in contact with the maxilla. Be- 

 low the maxillary notch the jugal fuses with the lachrymal and is 

 attached to the maxilla. The jugal is a very slender bone and ex- 

 tends backward beneath the orbit to the anteroventral angle of the 

 zygomatic process. 



The zygomatic process of the squamosal is thickened dorsoventrally 

 and is in contact with the postorbital portion of the supraorbital 

 process. As a whole the zygoma is robust, curved, and rather long ; 

 the dorsal outline curves gradually forward and upward. The post- 

 glenoid portion of the zygoma curves backward and then forward. 

 The greatest length of the right zygoma along the glenoid face is 

 98.5 mm. and the greatest depth anteriorly is 24 mm. 



In this specimen the crest formed by the contact of the supra- 

 occipital and frontal is the highest point in the dorsal profile. The 

 dorsal outline of the skull slopes forward from the crest and in the 

 region of the nares the declivity is more accentuated, but further 

 forward the slope is more gradual. On each side of the vertex and 

 in front of this crest the frontal plate of the maxilla is depressed, 

 forming a well-marked concavity. The supraorbital process of the 

 frontal and the superimposed maxilla rise above the premaxilla in 

 front of the nares. The temporal fossa is longer than the orbit and 

 its upper border is relatively straight, due in part to the lateral ex- 



