ART. 28 SKULL OF ZARHACIIIS FLAGELLATOR KELLOGG 11 



less flattened and slopes obliquely upward and inward. There is 

 no distinct preorbital apophysis, but the postorbital projection is 

 rather long and attenuate. The orbit is relatively longer than in 

 Lipotes. The lachrymal and jugal are missing. 



As on the first skull, the zygomatic process of the squamosal is 

 greatly thickened dorso-ventrally in contrast to the long attenuate 

 process of Inia and Lipotes. As viewed from the side, the slope of 

 the posterior half of the dorsal profile of the zygomatic process is 

 very steep; the inferior profile is biconcave. The anterior extremity 

 is bluntly pointed; the postglenoid process is relatively thin and 

 curves forward. The greatest length of the right zygomatic process 

 along the glenoid face is 98 mm. and the greatest depth near the 

 middle is 57.5 mm. 



Attention has already been called to the distortion which has 

 resulted from crushing. In addition to the previously mentioned 

 details, it may be noted that the lateral platelike extension of the 

 frontal and the superimposed maxilla have been depressed below 

 their original level. A thin layer of matrix lies between the upper 

 surface of the anterior half of the zygomatic process and the bones 

 mentioned above. 



The temporal fossa is relatively short and produced backward 

 beyond the level of the main body of the supraoccipital. Within 

 the fossa the parietals and frontals have buckled as mentioned before, 

 producing some irregularities. As in Inia and Lipotes, the parietal 

 is more or less crescentic in shape; it curves around the squamosal 

 on the external wall of the braincase and contributes the posterior 

 border of the temporal fossa and the external plate of the bipartite 

 lambdoid crest, extending downward behind the squamosal until it 

 meets the exoccipital on the lower margin of the temporal fossa. 

 Anteriorly and superiorly, the parietal is suturally united with the 

 frontal and inferiorly it abuts against the alisphenoid. The lateral 

 extremity of the exoccipital is relatively thin and is directed back- 

 ward. The condyles are large, knoblike in contour, and project 

 beyond the level of the exoccipital. Most of the lower border as 

 well as the anterior end of the external reduplication of the pterygoid 

 is missing, exposing the axial ridge of the vomer. The falcate process 

 of the basioccipital does not project below the postglenoid process. 



Ventral view. — The description of the rostrum in the preceding 

 paper fully covered this part of the skull and it seems unnecessary^ to 

 repeat some of the peculiarities in the present paper, especially as 

 no additional structural details are shown. It will also be noted 

 that the palatal surface of this skull (pi, 5) is not as well preserved as 

 on the first skull. Some additional details are revealed which 

 necessitate a modification of the interpretation given for the relations 

 of the pterygoids on the first skull. 



