VON IHERING’S RESEARCHES 
383 
tinct. All the more modern families of these continents show 
scarcely any traces of relationship to one another. Conse¬ 
quently we must conclude with Dr. Ortmann and several other 
authors who have definitely expressed themselves on the geo¬ 
logical age of the former land bridge between South America 
and Africa, that the latter ceased to exist before Tertiary 
times. 
Dr. von Ihering* did not limit his studies in South America 
to the fauna, he likewise urged, contrary to the opinion 
held by most botanists, that the floras of South America and 
Africa pointed unmistakably to the existence of his “ Arch- 
helenis.” His arguments were so convincing that Professor 
Englerf adopted his views after a very careful and critical 
examination of the problem from a botanical aspect. He ac¬ 
knowledged that for a long time he had looked upon the theory 
of a former land connection between South America and Africa 
with scepticism, chiefly on account of the great intervening 
ocean depths and the marked endemism in the flora of the two 
continents. After discussing the various means of accidental 
dispersal, and eliminating those plants which might possibly 
owe their presence in both continents to some of the known 
modes of occasional transport, he was impressed by the cir¬ 
cumstance that there was still a residuum of species, genera 
and families which must have had another origin. He urged 
that the distribution of the Strelitzioidae, whose fruits cannot 
be dispersed by wind, also that of some of the water plants of 
Africa, which have very near relations in South America, and 
others might be accounted for by the supposition of the former 
existence of a series of large islands in the Atlantic Ocean 
separated by narrow channels. All the same ho prefers a 
complete land bridge between the two continents. 
Dr. Arldt J discusses the problem in a very effectual manner 
both from a biological and a geological point of view. Like 
Dr. Ameghino, however, he is led to the conclusion that even 
in early Tertiary times South America was still directly joined 
* Ihering, H. von, “ Das Neotropische Florengebiet.” 
f Engler, A., “ Floristische Verwandtschaft zwiscken Afrika and 
Ainerika,” pp. 50—51. 
t Arldt, Tk., “ Entwicklung der Ivontineute,” p. 451. 
