No. 448.] 



DENTITION OF RHYNCHODUS. 



299 



and its present whereabouts are unknown'. The so-called 

 hchyrhiza antiqua is stated by Leidy to occur in New Jersey, 

 North and South Carolina, New Mexico and Mississippi, but the 

 differences between this and /. minx are inappreciable, and the 

 two were finally pronounced identical by their author. Certain 

 hypural fans similar to those accomi)an\ ini; rrotosiiliN iM'ua 

 in the Kn<2;lish Greensand have been thi-nrciu ail\ :ism n latc'd 

 with Ischyrhiza, but with questionable [)r()piKt\.' \.. uM>ons 

 have been assigned for making this assoi latien. aiul Mthci um- 

 sidcrations militate against it, lience it ai)pLMi> advisable to 

 exclude these fans altogether from the same -eiui^. 



The wide geographical distribution enjined 1)) ()iuh()>auiu> i> 



also in the Upper Cretaceous of l\gypt. In 1SS7 a l-.oth 

 differing from the tvpe species only in unimi)()rtant ])artuulai.s 

 was described by Darner from the Sennnian of (ii/eh under the 

 name of TitanUhthys pharao, the generic title- being Mihsetiuent 1) 

 changed to Ciigantichthys. Dames' figure was u)])ied b\ Ziitel 

 in his "Handbuch"/' and the two authors agree in plai ni- thi> 

 form in the vicinity of Knchodus, although -Isehxrhi/a" i> 

 referred by Zittel in the same work to the i:><H ida . i he latiei 

 position was first suggested by Cope, and hkeui^e adopted 

 by (). P. Hay.^ It will be .een. therefore, that theie 1^ ,.oo<l 

 authority for regarding Onchosaurus as one ot" the eail> toie- 



