ART. 19 A MIOCENE POEPOISE FEOM MAEYI^\.]SID— KELLOGG 17 



is fused posteriorly with the lachrymal and its, basal portion is 

 deeply mortised into the maxilla. An extremely slender and almost 

 threadlike styliform process of the jugal extends below the orbit 

 from the antorbital notch to the anterior face of the zygomatic- 

 process. On the first skull, the styliform process of the jugal (pL 

 4) is preserved in its entirety on the right side, but in consequence 

 of crushing has been slightly displaced from its original position 

 and now rests superimposed upon the coronoid border of the 

 mandible. ; 



Originally the temporal fossa was somewhat smaller than at 

 present (pi. 5, fig. 2) and taking crushing into consideration it is 

 apparent that its maximum length was not much gi'eater than one- 

 and one-half times the length of the orbit. Superiorly the temporal 

 fossa is bounded by the thin platelike lateral extension of the frontal 

 which underlies the maxilla and posteriorly by the lambdoid crest 

 which follows the lateral margin of the supraoccipital. In this fossa 

 the parietal is suturally united anteriorly and superiorly with the 

 frontal, posteriorly with the supraoccipital, and inferiorly with the 

 alisphenoid and squamosal. In shape the parietal bears some resem- 

 blance to a boot. It is clearly excluded from the dorsal surface of the 

 skull. 



As compared to that of Delphinodotv dividum-^ the z3^gomatic proc- 

 ess is shorter and deeper; it is thickened dorsoventrally and the an- 

 terior extremity is rather squarely truncated. The ventral margin is 

 more strongly curved than the dorsal; the postglenoid process is 

 short and rounded. The greatest length of the zygomatic process of 

 the second skull (Cat. No. 10670) along the glenoid border is 43. S 

 mm. and the greatest depth of the anterior extremity is 18.5 mm. 

 The condyles project posteriorly beyond the level of the exoccipitals. 



Ventrcd viern. — In addition to those characters which distinguish 

 it from both Delphinodon dwidwni and Acrodelphis scheynensis the 

 skull of Kentriodon pernix may also be recognized by certain struc- 

 tural peculiarities which can only be seen from a ventral view. Of 

 these the deep elongate depression in front of each respiratory pas-' 

 sage for the reception of the palatine, the relative width of the zygo- 

 matic process, and the number of alveoli for teeth are probably the 

 most conspicuous. As seen from below the skull of the second indi- 

 vidual (pi, 7) differs from Sotalia kicuxi mainly in the shape and 

 relations of the lachrymal bone. 



Inasmuch as the right mandible is crushed against the palate 

 of the skull associated with the skeleton (pi, 4) it did not appear ad- 

 visable to attempt any further removal of matrix in order that the 

 ventral surface of the rostrum could be studied. Hence this part of 

 the description will be based on the second skull (pi. 7) with such 



2994—27 3 . . ' ' 



