FOSSIL VA RA NID AE AND M EGA LA N ID A E. 
36a 
Saniva described by Leidy 1 and originating from the Eocene of Wyo¬ 
ming in Americ a, is also held by Nopcsa as a V a r a n i d and 
taking this supposition for granted the Nearctis should then also be 
involved in the history of the evolution of Varanidae. However Lydek- 
ker, Zittel (opp. ccit.) as well as Broili (1911) (op. cit. p. 216) range 
this problematical genus with the Anguidae so that, according to their 
opinion, it would not even be related to the Platynota but to the sub¬ 
order of Lacertilia vera ( = Kionocrania) . After a conscientious perusal 
of Leidy’s discretions and drawings, I am obliged to confess to the 
genus « Saniva » yet appearing a complete mystery to me. Neither the des¬ 
cription nor the drawings throw sufficient light on even the most impor¬ 
tant characters. The first question to ascertain would be whether the 
different fragments classified by Leidy with this genus truly belong to each- 
other? The humerus for instance presents a particularly bird-like ap¬ 
pearance, as Leidy himself very judicially remarks. The vertebræ on the 
other hand, do indeed resemble those of Varanus , although the figures 
allow no perspective as to the shape of the dorsal surface. It must be 
taken into consideration however, that the vertebræ of Anguidae and 
Varanidae in many respects bear great likeness to eachother, for which 
reason the resemblance .with Varanus cannot be judged as a decisive 
phenomenon. Moreover it does not seem impossible that the vertebræ 
will ultimately prove to belong to Varanidae and will thus have to be 
separated from at least a part of the remains left. 
Fürbringer’s assertion therefore has not yet been fully justified as 
to the Varanidae forming an «altweltliche Familie», although otherwise 
their being a «sehr eng geschlossene, streng genommen nur durch eine 
Gattung (Varanus) repräsentierte» family, may be maintained until more 
light is thrown on the subject. 1 2 3 In this declaration founded on minute 
genealogical researches, the expression «altweltlich» deserves particular 
consideration, in opposition to Arldt’s 3 opinion for instance. This sub¬ 
ject will however again be referred to in detail with regard to Saniva as 
also in the chapter treating of the phylogenetical relation of Varanidae ... 
With consideration to the geographical distribution existing in the past 
geological ages concerning the above, I must yet mention that the family 
Varanidae has up to this day only been found in an absolutely positive 
1 See Leidy’s works on this subject recorded in the literary references concer¬ 
ning Saniva (Chapter on System, «Appendix to the family Varanidae »). 
2 Fürbringer, Beitr. z. Syst. u. Geneal. d. Kept., Jenaische Zeitschr. f. Naturw.. 
XXXIV. Bd„ N. F. XXVII, Jena, 1900, p. 613. 
3 Entw. d. Kontinente u. ihrer Lebewelt &c., Leipzig, 1907 p. 276. 
