382 
ORIGIN OF LIFE IN AMERICA 
finally destroyed until early Tertiary times (compare Figs. 15 
and 20). Quite recently, however, Dr. Ortmann * argued that 
this “ Arclihelenis ” of Dr. von Ihering must have sunk 
beneath the waves of the ocean by the end of the Mesozoic Era. 
Some time ago Mr. Pocock f pointed out that the scorpions 
of the genus Opisthacanthus were confined to tropical Africa, 
Madagascar and South America. Our knowledge of the dis¬ 
tribution of scorpions has increased considerably since he 
wrote his essay, but the range of Opisthacanthus has not been 
greatly extended. It occurs in west, east and south Africa 
and Madagascar, while it reappears on the opposite side of the 
Atlantic in Colombia and the island of Haiti. It is not known 
from either Brazil or Guiana and may possibly have become 
extinct there. On the other hand, Damon, one of the Tarantu- 
lidae, occurs in west and east Africa and from Brazil to Pata¬ 
gonia. Professor Kraepelin f assumes that because the African 
Damon variegatus in a specifically identical form actually 
inhabits South America, it must have been introduced into the 
latter continent, yet in another place he urges that several 
of the centipedes (Scolopendridae) probably maintained their 
specific characters from archaic times to the present day. Like 
some of the species of Otocryptops, Rhysida and Scolopendra 
and the curious arachnid Cryptostemma, Damon variegatus 
may possibly represent one of these ancient species which 
has retained its morphological characters unchanged since 
Mesozoic times. 
The numerous examples, cited above, indicate that there 
exists a perfectly recognisable faunistic relationship between 
tropical Africa and tropical South America. Nevertheless this 
relationship rarely extends to genera and species. If so it is 
confined to forms like Anops, Mabuia, Subulina, Opistha¬ 
canthus, Cryptostemma and others, of which there is reason 
to believe that they are extremely ancient types. From some 
cause or other they may have retained their specific or generic 
characters throughout a series of geological ages. The faunas 
of Africa and South America as a whole are thoroughly dis- 
* Ortmann, A. E., “ Tertiary Archhelenis,” p. 242. 
t Pocock, B. I., “ Distribution of Arachnida,” p. 229. 
f Kraepelin, K., “ Scorpiones and Pedipalpi,” p. 240. 
