192 University of Kansas Geological Survey. 



Brachysaurus. 



Brachysaurus Williston, Kans. Univ. Quart., vi, 1897. 



Premaxillary probably obtuse. Frontal large and broad, 

 Suprastapedial process of quadrate united with infrastapedial 

 process. No median basioccipital canal. No zygosphene ; chev- 

 rons coossified. 



This genus is yet in large part unknown. As will be seen, 

 there are many striking points of resemblance to Progna- 

 thosaurus, and I am inclined to suspect that the two genera 

 may yet be found to be identical. The chief distinction, 

 and which, if true, will certainly distinguish the genera, is the 

 union of the chevrons. In Prognathosaurus they are free, while 

 in Brachysaurus they are coossified, or at least some of them are. 

 The entire chevrons are not preserved in any specimen, but the 

 broken ends indicate clearly that the union was not by articula- 

 tion. Dollo states, on page 298 of the work cited, that the chev- 

 rons are coossified in Prognathosaurus , but on the following page 

 that they are free. In a later publication, however, he says that 

 they are free, as determined from additional specimens. If the 

 bone I identify as a part of the pterygoid is really that, the teeth 

 are very large, thus agreeing with the most striking character 

 of the genus Prognathosaurus. The species has been described 

 in the foregoing papers, and will be found figured in plates xxx 

 and lxii. Typical species, B. overtonii Williston, Kans. Univ. 

 Quart., in, 169, 1895. Geological horizon, Fort Pierre Creta- 

 ceous of South Dakota. 



Holosfturus. 



Holosaurus Marsh, Amer. Journ. Sci., Jan. 1880. 



Nothing further is known of this genus than the original 

 description by Professor Marsh. Whether it is a good genus or 

 not cannot be stated with any degree of certainty. The only 

 essential character given by the author to separate it from 

 Platecarpus is the non-emargination of the coracoid. As this 

 same character is disregarded in.CUdastes, it would hardly seem 

 to be of value in this, if there are no other characters. 



