ALLEN: BATS OF THE GENUS CORYNORHINUS. 335 



that the outermost incisor (r^) is the one lost in all known Chiroptera. 

 In the specimen of Corynorhinus mentioned (C. m. toivnseyidii, Biol. 

 Surv. Coll. 150273, from Happy Camp, California) it is evidt 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 be.'n added at the outer side, — is in fact the i^ 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. It is a 

 very little shorter than i^ 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 P that has been lost in the Chiroptera, but that in 

 this case, it was probably a larger tooth than i^ 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 AUeghenies, 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 townscndii 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 



