194 University of Kansas Geological Survey. 



The average length of these, according to the measurements, is 

 about three inches each, 'making ninety inches. The bones of 

 the tail decrease in length rapidly in the tail, the length of the 

 entire tail never being as great as the trunk in front of it. Six- 

 teen feet, it is thus seen, is a large estimate of its length. If 

 the specimen is greater than that, the proportions would furnish 

 sufficient generic difference from Platecarpus. The type speci- 

 men is now on exhibition in the Yale Museum, and it will be 

 an easy matter to determine the characters. 



Cope has believed that this genus is identical with Sironectes. 

 The last genus, if genus it be, differs from Platecarpus in the func- 

 tional zygosphenes. HJffolosaurus abruptus has such zygosphenes, 

 and it is not at all improbable that it may, the synonymy would be 

 extremely probable. It is thus not at all impossible that Clidastes 

 planifrons Cope, Sironectes anguliferus Cope, and Holosaurus ab- 

 ruptus Marsh, are all identical. 



Pit osphorosaurus. 



Phosj)horosarus Dollo, Mem. Soc. Belg. Geol., in, 280, 1889. 



Suprastapedial process of quadrate much elongated and 

 united below with the infrastapedial process, inclosing an elon- 

 gated auditory meatus ; tympanic cavity extended and shallow. 

 Frontal bone very narrow, with nearly parallel sides, and form- 

 ing a part of the superior border of the orbits. Parietal bone 

 small, with a triangular superior surface and a very large 

 pineal foramen, bordering upon the frontal. Prefrontal not 

 projecting into a horizontal plate. Type species, P. ortliebii 

 Dollo, Brown Phosphatic Chalk, of Mesvin, Belgium. 



Although this genus is yet incompletely known, the parts 

 now known present very distinct and important differences 

 from the corresponding ones of any other known genera. The 

 genus is, seemingly, one of the most singular yet described, and 

 further knowledge concerning it will be looked for with much 

 interest. Just what are its nearest relationships, one cannot 

 now say, but I believe that it will be found to be a member of 

 the Platecarpime. 



