ALLEN: BATS OF THE GENUS CORYNORHINUS. , 335 
that the outermost incisor (7%) is the one lost in all known Chiroptera. 
In the specimen of Corynorhinus mentioned (C. m. townsendit, Biol. 
Surv. Coll. 150273, from Happy Camp, California) it is evidi nt from 
the agreement in form, that the two inner incisors correspond with the 
two normally present in the genus, and that the supernumerary one 
has been added at the outer side,— is in fact the 7? usually missing in 
all living bats. In outline (Plate 1, fig. 1) this tooth is roughly a 
right-angled triangle with its height a little less than its base. Itisa 
very little shorter than 7? but much stouter, and with a long base, 
rather than with the terete form characteristic of the second incisor. 
In crown view it has a broad cutting edge, as broad as the crowns of 
the other incisors. The skull of the specimen is unfortunately in 
fragments, and the corresponding teeth of the left side are lost, but 
the remaining teeth are normal. The case is instructive as indicating 
not only that it is 7° that has been lost in the Chiroptera, but that in 
this case, it was probably a larger tooth than 7? which is retained. 
GEOGRAPHIC DISTRIBUTION. 
The general limits of distribution for the genus are now fairly well 
ascertained. In the East it has been reported from Micanopy, 
Florida, in the northern part of the peninsula, but to the southward 
of that point there are no records. Northward it occurs throughout 
Georgia and South Carolina, to western North Carolina and Virginia. 
West of the Alleghenies, the northward limit of the range includes 
Kentucky, southern Indiana, and west of the Mississippi swings north 
again to southwestern South Dakota and the Yellowstone Park in 
northwestern Wyoming. Between the Rocky Mountains and the 
Sierra Nevada the records are few, but the genus undoubtedly is found 
in southern Idaho and in Nevada. On the west coast, Vancouver 
Island, British Columbia, seems to be the northernmost limit, and 
thence it ranges south in the Sonoran zones, to the tableland of 
Mexico as far as Oaxaca and Vera Cruz. Apparently it has not yet 
been discovered in the peninsula of Lower California. In general it is 
characteristic of the Austral zones as defined by Merriam, though in 
the northwest, the subspecies townsendii is mainly confined to the 
Transition and even enters the Boreal zone. This more northward 
range in the northwest is possibly indicative of a more extended 
northward distribution in ancient times, when we may assume that 
