240 University of California Publications in Zoology [Vov.17 
ORIGIN OF CALIFORNIA Bats 
The bones of bats are so small and delicate that they are very easily 
destroyed, and it is probably for this reason that they are compara- 
tively seldom found as fossils. In only two instances known to the 
writer have fossil bats been discovered in California. The palaeonto- 
logical collection of the University of California contains a skull which 
I have identified as Myotis longicrus, from Samwell Cave, Shasta 
County ; and in the same collection is a broken skull and several lower 
jaws of Antrozous pallidus from Potter Creek Cave, also in Shasta 
County. In both cases the horizon is doubtfully Pleistocene. 
Gregory (1910, p. 319) says of the origin of the bats: 
The group was very highly specialized as far back as the Eocene and the 
palaeontological evidence as to its origin is therefore of a negative character, as 
in the case of the Rodents, Edentates and all other groups which probably acquired 
many of their ordinal characters before the known Tertiary record began. 
Nevertheless there can be little doubt that the Chiroptera are an offshoot of late 
Mesozoic or early Tertiary arboreal Insectivores, which must have resembled 
Galeopithecus in many characters. 
It is of interest to note the present world-distribution of the eleven 
genera of bats found within the State of California. The ranges 
here given are from Miller (1907). Four genera occur in both the 
Old World and the New. These are: Myotis, found in both hemi- 
spheres to the northern and southern limits of tree growth; Pipistrel- 
lus, found in the Eastern Hemisphere to the limits of tree growth, but 
in the Western Hemisphere confined to North America from the 
northern United States (except in the Boreal zone) to southern Mex- 
ico; Nyctinomus, found in the warmer portions of both the Eastern 
and the Western hemispheres; and EH ptesicus, found in Afriea, Mada- 
gascar, Australia, Asia (except the Malay region), and America from 
southern Canada southward (exeept Lesser Antilles). 
Of the seven genera confined to the New World, Nycteris is the 
most widely distributed, occurring in North America northward to 
the limit of tree growth and southward to include the Bahama Islands 
and Greater Antilles, as well as the Galapagos and Hawaiian Islands. 
Lasionycteris occupies northern North America, south through the 
United States. Antrozous is found in western North America from the 
Columbia River to central Mexico. Corynorhinus occurs throughout 
the warmer portions of North America to southern Mexico. Macrotus 
occurs in the warmer parts of North America from Guatemala to 
