A NEW GENUS OF FOSSIL CETACEANS FROM SANTA 

 CRUZ TERRITORY, PATAGONIA; AND DESCRIP- 

 TION OF A MANDIBLE AND VERTEBRA 

 OF PROSQUALODON 



By FREDERICK W. TRUE 

 Head Curator of Biology, U. S. National Museum 



With Three Plates 



Some months ago Prof, W. B. Scott, of Princeton University, 

 placed in my hands for study two specimens of fossil cetaceans 

 from Patagonia, one of which proves to belong to an undescribed 

 genus ; the other represents the genus Prosqualodon, and affords 

 new information regarding the mandible, teeth, and vertebrae. 



The first of these specimens (No. 15459) comprises two large and 

 two small fragments of a skull of a fossil toothed whale, collected 

 by the late J. B. Hatcher, April 24, 1899, in the Patagonian Beds at 

 Darwin Station, Santa Cruz Territory, Patagonia. Upon examina- 

 tion it proves to be an undescribed form, allied to Inia, but much 

 larger. In order to bring it to the attention of cetologists I propose 

 to describe it under the name of 



PROINIA PATAGONICA, new genus and species 



The specimen consists only of the cranium, from which the ros- 

 trum has been broken oft' immediately in front of the blowholes. It 

 has been strongly compressed vertically, so that the basioccipital and 

 supraoccipital are nearly in the same plane. The blowholes have 

 also been forced backward and upward. All the under parts of the 

 skull anterior to the basioccipital, together with the earbones, jugals, 

 and the right zygomatic process are lacking. 'The remaining parts 

 are in a good state of preservation, but the surface and contours 

 have been considerably modified by excessive chiseling. 



The skull resembles Inia more closely than it does any other 

 recent or fossil form with which I am acquainted, but is much larger. 

 The most salient points of resemblance are the strongly elevated 

 vertex, consisting of the large, rectangular anterior median pro- 

 cesses of the frontal; the relatively narrow orbital plates of the 

 frontal; the anterior position of the orbit; the quite large temporal 



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