ART. 14. MARYLAND FOSSIL POEPOISE KELLOGG. 9 



Cetacea. » * * All things considered, the brain of Platanista is wanting 

 in the broad rotundity of the whale group generally and so marked in Orcella. 

 To a very limited degree it has Elephantine characters, viz, height and 

 moderate breath, though one can not regard it in any other light than that 

 of a modified Cetacean form. 



The eyes of the Ganges River dolphin are of small size and prob- 

 ably do not function beyond conveying sensory impressions of 

 varying degrees of light and darkness. Functional eyes would be of 

 relatively little use in the muddy waters of the Ganges River, 



The relations of the basicranial bones suggest that the rostrum and 

 brain case have been telescoped together to a greater extent than in 

 other river jDorpoises. To recapitulate the evidence in favor of this 

 observation it might be pointed out that in correlation with the ros- 

 trum being depressed below the brain case, the nasal passages have 

 moved backward and are situated on a level with the enterior mar- 

 gins of the squamosals, the internal and external pterygoids extend 

 forward to the level of the maxillary notches and thus entirely con- 

 ceal the palatines, the opening for the infraorbital canal is within 

 the temporal fossa, the zygoma is in contact with the supraorbital 

 process of the frontal, the antero-posterior diameter of the supra- 

 orbital process of the frontal has been shortened and the process as 

 a whole deflected obliquely forward as would be expected to result 

 from a lowering of the rostrum, and the lachrymal has been pushed 

 inward and its posterior projection has been wedged into the maxilla 

 instead of being inserted between the maxilla and the supraorbital 

 process of the frontal as in Lipotes. In skulls of Lipotes and Inia, 

 the postpalatal axis bends downward from the axis of the rosrrum 

 while both axes of the Platanista skull lie in approximately the same 

 plane. 



Although there seems to be great diversity of opinion as expressed 

 in the published writings of many investigators regarding the alloca- 

 tion of the genus Platanista^ the majority agree that this genus bears 

 some relationship to Iiiia and Lipotes. Of course, one can only 

 surmise the incipient modifications which marked the development of 

 those types of porpoise skulls we now know either fossil or living. 

 In cases of the river porpoises, practically nothing is known about 

 their past geological history. Among the living forms, Platanista 

 may represent the most highly specialized type. The architecture 

 of the Platanista skull in the region around the palatines, as shown 

 above, is singularly modified in comparison with the conditions found 

 in Phocaena. Skulls of Lipotes and Inia represent advanced stages 

 of another type of cranial architecture. The basicranium of the Zar- 

 hachis slnill closely conforms with that of Platanista^ but the general 

 architecture of the dorsal face of the skull and rostrum agrees with 

 that of Lipotes. No comparisons can be made with Eoplatanista Dal 



