86 University of Kansas Geological Survey. 



were all later announced as new discoveries. With the excep- 

 tion of some brief and unimportant papers on the group by- 

 Morton and Leidy, the next most important contributions to 

 the, knowledge of the Mosasaurs are due to the late Professor 

 Cope. Aside from a number of short papers, his chief contri- 

 butions will be found in his ',' Synopsis of the Extinct Batrachia, 

 etc.," published in 1870, and his volume on the " Cretaceous Ver- 

 tebrata of the West," published in 1875. In this last work he 

 enumerates more than fifty species of the group from America. 

 Meanwhile Professor Marsh had described a number of forms 

 and published a number of discoveries concerning the anatomy 

 of these animals, many of which, however, were rediscoveries 

 of Goldfuss. These papers by Marsh will be found in the 

 American Journal of Science. To him is due the discovery of 

 the stapes, columella, transverse and hyoid, and the presence 

 of the hind limbs, which had already been indicated by Gold- 

 fuss. Since 1882, Dollo has very materially increased our 

 knowledge of this group, and has established the following new 

 genera in numerous papers : Plioplatecarpus, Hainosaurus , Prog- 

 nathosaurus, and Phosphorosaurus. In 1892 Baur published a 

 complete and minute description of the skull of Platecarpus, illus- 

 trated by detailed drawings of the different parts, and Williston 

 and Case gave for the first time a description of the vertebral 

 column and more precise knowledge of the extremities and the 

 general form of the Mosasaurs. Later papers by Williston have 

 added to the knowledge of the Kansas forms, and the first cor- 

 rect restoration of any member of this group was given by him. 

 In 1894 was published a valuable illustrated paper on the Kan- 

 sas Mosasaurs, by Merriam, in which several supposed new 

 forms were briefly described and a number of new details given 

 of the different genera, with more complete generic differences 

 than had hitherto been published. Other papers by Gervais, 

 Gaudry and Owen complete the list of the more important ones 

 on this group of reptiles. 



