MAY Q im 



Kansas University Quarterly 



Vol. IV. APRIL, i8g6. No. 4. 



On the Skull of Ornithostoma. 



BY S. W. WILLISTON. 



(With Plate I.) 



In the first volume of this Quarterly, the writer described briefly 

 a skull of Ornithostoma {Ftcranodon), correcting some important 

 errors which had been made by Marsh. The University of Kansas 

 lias recently come into possession of another skull, collected by 

 Mr. C. H. Sternberg in western Kansas, which adds some interest- 

 ing facts to those hitherto known. It is to be regretted that the 

 very faulty figure of Ptcraiiodoii published by Marsh stills finds 

 expression in different works, and especially that the recent edition 

 of Dana's Manual should be disfigured by it. The injured condi- 

 tion of the posterior part of the specimen from which the figure 

 was made had obliterated the supratemporal fossa, and in conse- 

 quence the orbits are represented as directed obliquely backward. 

 One need not call attention to the absurdity of representing an 

 animal with such a long and slender maxillary portion having eyes 

 that would look towards the back of the head. 



In the specimen from which the figures in Plate I are drawn, the 

 skull has been somewhat compressed obliquely from above down- 

 ward, and not laterally as is almost invariably the case. By a 

 careful comparison of the two sides the relative and natural condi- 

 tions of the parts have been made out with tolerable certainty. 

 From them it will be seen that the orbits are directed, as would be 

 expected, anteriorly, rather than posteriorly. The supratemporal 

 fossa is of considerable size and the occipital crest is limited to the 

 posterior part of the skull, not extending as a sharp ridge through 

 the whole length, as stated by Marsh. 



As is always the case with the Kansas specimens of these 

 creatures, sutures of the skull are for the most part wholly 

 obliterated, and therefore but little can be stated of the exact 

 relations of the different elements. 



(195) KAN. UNI. QUAB.. VOL. IV. NO. 4, APRIL, 1896. 



