F08SIL VA RA NID AE AND ME GALA NID AE. 
421 
examination of original material. Borne systematically insuffi¬ 
cient data may be gathered from the descriptions and figures in Leidy’s 
work already alluded to. The humerus described (p. 182) and figured 
Fig. 20. t Vaniva * maior Leid y hom inc. — Dorsal vertebrae from lower aspect and in 
profile. — Bridge Eocene (Wyoming). - From Leidy, op. cit., PI. XXVII, Figs. 36 — 37. 
(PI. XV, Pig. 14) by Leidy as belonging to S. maior is undoubtedly not 
reptilian and therefore cannot belong to Saniva. 
Habitant: Wyoming, America, 
CHAPTER III. THE GEOGRAPHICAL DISTRIBUTION OF THE 
VARANIDAE IN PAST AND PRESENT DAYS. 1 
It is truly no easy task to determine what may have been in earlier 
days the geographical distribution of this family and the direction follow¬ 
ed by its migration. Formerly, where Thinosaurus of the Wyoming Eocene 
strata was yet taken for Varanian, these remains being the most ancient ones 
regarded as such, it appeared natural to consider the Varanidce as N e- 
arctic forms becoming Holarctic in the course of their geo¬ 
graphical extension. This seems to have been Arldt’s opinion expressed 
in the following terms (op. cit., p. 274): «Wenn wir die Verbreitung der 
Reptilien innerhalb der holarktischen Region ins Auge fassen, so sind 
von den jetzigen Hauptvertretern der Klasse, den Lepidosauriern, 
eine Reihe von Familien auf die östliche Hämisphäre beschränkt. Soweit 
diese aber eine weitere Verbreitung besitzen, haben sie fast alle fossile 
Vertreter auch in Nordamerika, so die Eryciden bis zum Miozän, die Vara- 
niden bis zum Eozän. Dies spricht dafür, dass die modernen Lepidosaurier 
sich wie die Placentalier von Nordamerika aus über die Erde verbreitet 
haben, zumal sie nur wenig älter sind als diese, wenn auch ihre uns be- 
1 Concerning the palæogeographical maps joined to this work, it must be noted 
that in some even more important details, these maps differ from those of other authors, 
Lapparent’s for instance, though as regards the question interesting us, these differen¬ 
ces — arising from our present insufficient knowledge on Palæogeography — are not 
of any far-reaohing importance. 
