Baron Francis Nopcsa, Jun. — The Origin of Mosasaurs. 121 



Mosasaiirs, dififering from the latter only in not being as tborougUy 

 adapted for pelagic life. On the other hand, the Aigialosaiirs show, 

 as remarked by Kornhuber, a strong resemblance to the living Varnnids, 

 ■differing from these only in those points by which they approach the 

 Mosasaurs} 



The question arises now, do the Aigialosaurs represent the most 

 primitive Mosasaurs or a family in the suborder of the Lacertilia ? 

 Taking the Mosasaurs, on account of the development of their 

 paddles, as a distinct suborder of the Squamata, the Aigialosauridge 

 -would prove to be a distinct family among the Lacertilia, approaching 

 greatly the Jurassic type from which the Cretaceous Mosasaurs and 

 the recent Varanidse are the offspring. This type, being terrestrial, 

 would of course bear greater resemblance to the modern Varanids 

 than to the pelagic Mosasaurs. 



A paper dealing more fully with this highly interesting subject is 

 to appear in the Geolog. und Palaeontolog. Beitrage in Vienna. 



Papers referred to. 



^aitr.— "The Skull of Mosasaurs" : Journal of Morphology, 1892. 

 Bonlenger. — " Osteology of Heloderma " : Proc. Zool. Soc. 



London, 1891. 

 " Newly described Jurassic and Cretaceous Lizards " : Ann. & 



Mag. Nat. Hist., London, 1893. 

 Gorjanovic - Kramberger. — " Aigialosaurus " : Societas historico 



naturalis Croatica, Zagrab (Agram), 1892. 

 "Einige Bemerkungen zu Opetiosaiirus'" : Verhandl. k.k. geolog. 



Eeichsanstalt, Wien, 1901. 

 Kornhuber. — " Uber einen neuen fossilen Saurier " : Abhandl. k.k. 



geolog. Eeichsanstalt, Wien, 1873. 

 " Carsosaurus Marchesettii " : loc. cit., 1893. 

 " Opetiosauriis Bucchichi " : loc. cit., 1901. 

 Lortet. — "Reptiles fossiles du bassin du Rhone": Archiv Musee 



hist. nat. Lyon, 1892. 

 Merriam. — " Pythonomorphen " : Pal^eontographica, 1891, vol. xli. 

 Meyer. — " Acteosaiirus Tomasinii" : PalEeontographica, vol. vii. 

 Osborn. — "A complete Mosasaur Skeleton": Mem. Amer. Mus. 



Nat. Hist., 1900. 

 Owen — " Fossil Reptiles, Cretaceous Formation " : Palseontographical 



Society, 1851-1864. 

 Seeley. — " Adriosaurus Suessi" : Quart. Journ. Geol. Soc, 1881. 

 Willistou. — "Mosasaurs": University Geol. Surv. Kansas, 1898. 



1 It canuot be certainly knoAvn whether the pterygoids of the Aigialosaurs bore 

 teeth, but I am inclined to believe they did, since in Opetiosauriis the crown of a tooth 

 lying near the hyoid bone ( = columella of Kornhuber) seems to differ in size both 

 from the mandibular and (presumably also) maxillary teeth of this animal. 



