412 ORIGIN OF LIFE IN AMERICA 



whence it has spread as far north as southern Germany. 

 Several other species are peculiar to southern Europe and 

 Madeira. One Japyx is found in India. Across the Atlantic 

 Japyx subterraneus has been observed in the Mammoth Cave 

 of Kentucky, while a second species (Japyx saussurei) inhabits 

 only Mexico and Chile.* 



The curious scorpion-like Koenenia, the only genus of the 

 order Palpigradi, is confined, as already mentioned, to 

 southern Europe, Texas and Chile. As far as America is 

 concerned, it is limited in its range to the two regions alluded 

 to. The family of spiders, Mecicobothriidae, according to 

 Mr. Pocock,f occurs only in the western States of North 

 America and in Argentina, the genus Hexura being found in 

 the former and Mecicobothrium in the latter part of America. 



The ancestral form of the evidently very ancient family of 

 earthworms, Megascolecidae, seems to be Notiodrilus. This 

 genus is met with in America only in Mexico, Guatemala, 

 Chile, Argentina, Patagonia, Tierra del Fuego and the Falk- 

 land islands, while another genus, namely, Kerria, inhabits 

 Lower California and southern South America, being absent 

 from the intermediate area. The slug Philomycus has a wide 

 range in North America, occurring in Mexico, Guatemala and 

 Costa Rica, and then turns up again far away to the south 

 in Chile. Similarly the salamander Plethodon, which in North 

 America inhabits principally the western States, is found in 

 a single district in South America, namely, in Argentina. 

 There are a large number of similar examples among such 

 forms of insects that we have reason to believe date back 

 to at least early Tertiary times. The best known example, per- 

 haps, is that of the common northern genus Carabus. In 

 Mexico there are still two species. Neither in Central 

 America, nor in northern nor .middle South America has it 

 been discovered, while in Chile and Tierra del Fuego there 

 are nine species. That the latter are now considered suffi- 

 ciently distinct to be placed into the separate genus Cero- 

 glossus does not alter the fact that they are closely related 

 to northern Carabi, whereas they have no affinity at all with 



* Karsch. F., "Neue Fundorte von Japyx," p. 154. 



t Pocock, R. I., " Geographical Distribution of Spiders," p. 346. 



