246 
ORIGIN OF LIFE IN AMERICA 
within recent years the remains of a small insectivore have 
been met with in the early Tertiary Santa Cruz deposits of 
Patagonia. This mammal, according to Professor Scott,* is 
genetically related to the African golden moles. The South 
American Necrolestes, as it has been called, is certainly more 
primitive in structure than its African relations. Moreover, 
in .western North America fossil mammals have been dis¬ 
covered both in Oligocene and Miocene strata which have been 
referred to the same family Chrysochloridae. It is true that 
Dr. Matthew f is now inclined to place the Oligocene Apter- 
nodus among the nearly related family Centetidae, but the two 
other genera Xenotherium and Arctoryctes are still looked 
upon as true chrysoehlorids. A possible land connection 
between Africa and South America will be discussed later on. 
Whether Patagonia was the original home of the chryso- 
chlorids or South Africa we cannot tell, but the family may 
possibly have spread from South America to North America 
by utilising the hypothetical land bridge that I think lay to 
the west of the present continent. 
A few words of appreciation of the splendid work that has 
been done in making us acquainted with the rich fauna and 
flora of Central America are due to Mr. Godman. For years 
he and Mr. Salvin laboured with great industry and at con¬ 
siderable expense in bringing together an immense collection 
of vertebrates and invertebrates, subsequently publishing the 
series of beautifully illustrated volumes of the “ Biologia 
Centrali-Americana ” in which the results of their studies were 
made known to the scientific world. In the volume describing 
the botany of Mexico and Central America there is an excel¬ 
lent summary dealing with the constituents of the flora and 
their relationships. No such summary has been attempted in 
the other volumes, so that Mr. Ilemsley’s account of the plants 
of Mexico and Central America is of particular value to those 
who are engaged in a study of the zoogeography of that region. 
The first item of interest is one which we have noticed 
occasionally among apparently very ancient groups of North 
American animals. Genera like the amphibians Spelerpes 
and Amblystoma, which have their headquarters in Mexico, 
* Scott, W. B., “Report of Princeton Expedition.” Yol. Y. 
t Matthew, W, D., “The Skull of Apternodus,” p. 35. 
