RATS ON GALAPAGOS ISLANDS 
299 
Oryzomys galapagoensis he found a second distinct form 
which he named Oryzomys bauri. 
A more important natural history survey of the islands 
was made by the Hopkins Stanford Expedition in 1898. In 
addition to the mammals already known from the archipelago, 
it was discovered that Narborough, Indefatigable and Sey¬ 
mour islands are inhabited by rice-rats, which show such 
structural distinctness in the interorbital portion of the skull 
that Mr. Heller * proposed their being placed into the 
new genus “ Nesoryzomys.” Four mouse-like mammals are 
thus known to he peculiar to the Galapagos islands, viz., 
Oryzomys galapagoensis, 0. bauri, Nesoryzomys indefessus 
and N. narboroughi. The only other terrestrial mammal not 
found elsewhere is Atalapha or, as it is now called, 
Lasiurus brachyotis. 
It is interesting to note that the genera to which these 
species belong are characteristically American. Both Ory¬ 
zomys and Lasiurus have a wide range in North and South 
America as well as in the Antilles. We have learned that 
Oryzomys antillarum is confined to Jamaica. Another species 
lives on St. Vincent, and several more on Trinidad, while a 
species (0. nelsoni) is peculiar to the Tres Marias islands off 
the west coast of Mexico. A genus ranging from New Jersey 
in the north to Tierra del Fuego in South America, with a 
large number of species, must be a very ancient one; and 
yet not a single species occurs outside the New World. 
I have never hitherto alluded to bats because they are so 
generally regarded as of little value in faimistic problems. 
Specialists of this group, such as Dr. Knud Andersen,f in¬ 
form us, however, that this assumption is by no means correct, 
and that in most cases bats are as good and reliable zoogeo- 
graphical guides as other small but non-flying mammals. 
The fact that although Lasiurus is found from Canada to 
Patagonia it has nevertheless preserved its original habitat 
in the New World, and has not even crossed Bering Strait into 
Asia, would seem to support Dr. Andersen’s contention, while 
its antiquity is vouched for by the occurrence of distinct 
species of Lasiurus on several remote American islands. 
* Heller, Edmund, “ Mammals of Galapagos Archipelago.” 
t Andersen, K., “ Geogr. Distribution of Bhinolophus,” p. 652. 
