24 PROCEEDINGS OF THE NATIONAL. MUSEUM. vol.60. 



relate to the bony structure, thus making the definition applicable 

 to the fossil members of the family, and add remarks of my own 

 on the presence of a vestigal zygosphene. 



The Varanidae or Monitors form a group comprising both recent 

 and fossil representatives. In 1918 Fejervary^^ listed 43 forms as 

 being referable to the family Varanidae. Forty-one of these pertain 

 to the genus Va/ranus and two to the genus Saniwa; the latter, al- 

 though included under the Varanidae, was regarded by him of 

 " Uncertain s^'stematical position." 



His more extended remarks ^® are quoted in their entirety below : 



It must be here remarked that the genus Saniva described by Leidy and 

 originating from the Eocene of Wyoming, in America, is also tield by Noposa 

 as a Varanid, and talcing this supposition for granted, the Ne(i7-tis should also 

 be involved in the history of the evolution of the Varanidae. However, Lydek- 

 ker, Zittel (op. cit.), as well as Broili (1911) (op. cit., p. 216) range this 

 problematical genus with the Angiiidae, so that, according to their opinion, it 

 would not even be related to the Platynota but to the suborder of Lacertilia 

 vera (= Kionocrania) . After a conscientious perusal of Leidy's descriptions 

 and drawings, I am obliged to confess to the genus Saniva yet appearing a 

 complete mystery to me. Neither the description nor the drawings throw 

 sufficient light on even the most important characters. The humerus, for in 

 stance, presents a particularly birdlike appearance, as Leidy himself very 

 judicially remarks. The vertebrae, on the other hand, do, indeed, resemble 

 those of Varanus, although the figures allow no persiiective as to the shape 

 of the dorsal surface. It must be taken into consideration, however, that 

 the vertebrae of an Angvidae and Vara?iidae in many respects bear great like- 

 ness to each other, for which reason the resemblance with Varanus can not 

 be judged as a decisive phenomenon. Moreover, it does not seem impossible 

 that the vertebrae will ultimately prove to belong to Varanidae and will thus 

 have to be separated from at least a part of the remains left. 



The observation recorded above is a very logical and concise sum- 

 mary of the status of the genus Saniioa, based on the scanty informa- 

 tion then available (1918) to Fejervary. 



The more recent preparation of the t3'pe materials, however, now 

 shows the genus Saniwa to be based on an adequate specimen, and 

 it thus removes some of the uncertainties of which Fejervary justly 

 makes mention. 



The incompleteness of the postorbital bar; the toothless palate; 

 pterygoids and palatines, widely separated ; infraorbital fossa 

 bounded by pterygoid, palatine, and transverse, the maxillary being 

 excluded; pleurodont dentition; teeth pointed; dorsal centra with 

 flattened haemal surfaces devoid of carina ; and the absence of der- 

 mal scutes constitute a combination of characters, together with the 

 close resemblance of most of the bones of the skeleton to the living 



« Ann. Mus. Nat. Hung., vol. 16, 1918, pp. 444-445. " Idem, pp. 362-363. 



