(ienus Lysorophus, Cope. 233 



There is no lack of material. The Chicago Museum has 

 200 nodules, each containing much of the skeleton of a 

 specimen : the American Museum, New York, also has 

 many nodules, and in the American Museum nine skulls 

 have been chiselled out, one or two in very good condition. 

 In Tiibingen there are 24 skulls, and at Munich a consider- 

 able number more. 



As the extensive literature has been reviewed by Williston 

 and others, it will be unnecessary to enter into this in detail. 

 To Broili we owe the first really good figures of the skull, 

 but there are one or two points in his interpretation that I, 

 in common with all later writers, do not accept, and from 

 his conclusion as to the affinities of the genus I also differ. 



Case gives a brief description of the more conspicuous 

 elements of the skull, and reproduces Broili's and Williston's 

 figures. As these two figures differ in a number of points, 

 one could have wished that Case had given an original 

 figure of his own interpretation, and his description, while 

 pointing out the different views, does little to clear up the 

 matter. 



Williston gives us clear definite views as to the structure 

 of the skull and skeleton, and equally clear opinions as to 

 the affinities of the genus. 



Von Huene, the latest worker on the genus, has just issued 

 a paper on Lysorophus in the ' Anatomischer Anzeiger,' and 

 another paper is in the press describing the specimens in 

 the American Museum. Though these two papers are 

 appearing in the same year, I believe that the one in the 

 ' Anatomischer Anzeiger ' to be the later. On one or two 

 points the opinions expressed differ in the two, and it is 

 therefore well to know which is the latest. Von Huene has 

 figured a number of the better skulls in the American 

 Museum, and gives us clear opinions not only on the 

 structure, but also on the affinites of the genus. 



The skulls in the American Museum, though comparatively 

 few in number, are mostly well preserved, and there is 

 scarcely a point in the structure that cannot be made out 

 in one or other. 



The best figures published of the top of the skull are those 

 of Broili and Williston, and they differ, apart from inter- 

 pretations, only in the relative width of the nasal region. 

 While neither is altogether correct, a composite of the two 

 would give the truth. The difference arises from the 

 peculiar state of affairs in front of the prefrontal. Broili 

 correctly recognises a round opening here which he regards 

 as the nostril. It is also shown in Williston's specimen. 

 The most natural conclusion would seem to be that this is 



