MAMMALIA. 89 
continent. Coupling this inference with the absence of extinct Monkeys in North 
America and of Lemurs in South America, the view that the ancestors of the Platy- 
rhini entered South America from Africa is at all events provisionally defensible. 
Order INSECTIVORA. 
America is not rich in members of this order. Two families, the Talpide (Moles) 
and Soricide (Shrews), occur in North America. Although the Talpide range as far 
south as the Southern States, they do not appear to enter Mexico or Central America. 
The Soricide, on the contrary, are represented in Central America by the three genera 
Sorex, Cryptotis (sometimes regarded as a subgenus of the North American Blarina), 
and Notiosorer. Of these, Sorex has a wide range over Europe, Asia, and North 
America, and passes at high altitudes through Mexico to Guatemala; Notiosorex 
inhabits the Southern States of North America (Texas etc.) and Mexico (Sinaloa, 
Jalisco). Cryptotis, which replaces in Central America the North American genus 
Blarina*, ranges mostly at high altitudes through Central America (Mexico, Yucatan, 
Guatemala, Nicaragua, Costa Rica) to Colombia, Venezuela, and Guiana. 
Shrews related to Sorex and Blarina have been recorded from the Oligocene of 
Europe and North America, and Sores itself goes back to deposits of that age in Europe, 
appearing in North America in the Pleistocene, and since no Insectivores of this group 
occur in South American deposits f, it seems clear that the Central American species 
are southern migrants from North America. 
Order CHIROPTERA. 
The Central American genera of this order, fifty or more in number, are assigned 
to eight families—the Emballonuride, Noctilionide, Phyllostomide, Desmodontide, 
Natalide, ‘Thyropteride, Vespertilionide, and Molosside {. Geographically these 
families may be referred to two categories: the first containing the Vespertilionide, 
Molosside, and Emballonuride, which are represented in the Old World as well as in 
America ; and the second containing the remaining five, which are mostiy restricted to 
Central and South America, a few genera only occurring in the Southern States of 
North America. Of this second category, by far the most important numerically are 
the Phyllostomide, the American Leaf-nosed Bats §, the genera of which, occurring in 
* A species of Blarina has been recorded from Costa Rica, but there seems to be some doubt about the 
correctness of the locality. 
+ The only extinct South American Insectivore known is Necrolestes of Upper Miocene age, the nearest 
ally of which appears to be the Golden Mole (Chrysochloris) of South Africa, 
+ Pending the completion of Dr. Knud Andersen’s ‘ Monograph of the Chiroptera,’ in course of publication 
by the Trustees of the British Museum, the classification and nomenclature here followed are those of Miller 
(Bull. U.S. Nat. Mus. lvii. 1907). . 
§ The Leaf-nosed Bats of the families Rhinolophide, Hipposideride, and Megadermide are restricted to 
the Old World. . 
BIOL. CENTR.-AMER., Introd. Vol., June 1915. N 
