'880 
G. J. DK FEJ EK VAR Y 
(Csarnóta, Beremend). These combinations arc naturally only 
based on the palaecgeographical and palaeontological data we presently 
dispose of, and material at hand is certainly not sufficient for elucidating 
the question in its details. The geographical distribution will moreover 
be yet discussed further on, palaeogeographical conditions being here 
only mentioned to prove that the latter, from a biological point of 
view, cannot have so far dissociated V . Hofmanni from V. marathonensis, 
as to oppose any objection to their being considered as one and the same 
species. Let us now go over to the other important factor of biological condi¬ 
tions represented by climate. As stated in competent literature 1 2 
the climate which during the Miocene had been hot, da m p and s u b- 
tropical, gradually changed into Pliocene mediterranean clima¬ 
tic conditions. About German Miocene Frech 2 writes as follows: 
«Das häufige Vorkommen von Palmenstämmen in der Braunkohle des. 
Königreiches Sachsen, in Thüringen und bei Bonn deutet darauf hin, daß 
sich auch nördlich der erst in der folgenden Miocänzeit aufgewölbten Alpen¬ 
kette ein subtropisches Klima wieder einstellte.» At the beginning 
of the Miocene therefore, according to Kayser, 3 the climate was 
«recht warm und feucht» notwithstanding traces of the influence of frost 
having been established on certain fossil leaves originating from the lower 
Miocene, which phenomenon, in the course of the Tertiary period, 
cannot however be considered as yet marking a refrigeration of the 
World’s climatic conditions in general. 4 Thus despite subtropical climate, 
V . Hofmanni may have been exposed to the influence of cooler weather in 
the lower Miocene already, —just as is the case with the recent V. gri¬ 
seus inhabiting still the temperate regions around the Caspian Sea. Succee¬ 
ding the Miocene, the Pliocene mediterranean climate gradually 
cooling down (in Northern and Central Europe) advances towards the 
Glacial period. Neither can therefore the difference in temperature existing 
between the subtropical and mediterranean climate be consi¬ 
dered — again referring to the example of the recent V. griseus — as a suffi¬ 
cient biological cause for the establishing, from that point 
of view, a necessary postulatum of a variation between V. Hofmanni 
and V. marathonensis. In consequence of the tolerably uniform nourishment 
of Monitors the respective fauna coming into consideration can 
1 Kayser, op. cit., 1915, p. 338; W. R. Eckardt, Palænklimat.. Sanami. Göschen, 
Nr. 482, Leipzig, 1910, p. 105-108. 
2 Aus d. Vorzeit d. Erde, Bd. V, (Aus Nat. u. Geistesw., Nr. 211) Leipzig, 1911, 
p. 118. 
3 1. c. 
4 Eckardt, op. cit., p. 51 — 52. 
