84 



BULLETIN" 144, UNITED STATES NATIONAL MUSEUM 



to contain adult males as well as adult females. Thus of 21 bats 

 from Nickajack Cave, Tenn., August 31, 15 were adult males, 6 adult 

 females; and of 9 from Rosiclare, 111., August 14, 4 were adult males, 

 5 adult females. Presumably pairing takes place in the fall, after 

 which the sexes probably segregate until the following August. At 

 all events, 17 specimens taken April 14 at Indian Cave, Tenn^ 

 were all females. Again, a series of 18 from Fort Deposit, Ala., 

 June 18-19, proved to be all males, while of 12 adults taken a little 

 later, July 9, at Rogersville, Ala., all but 1 were females. 



Remarks. — Superficially^ Myotis gi'isescens resembles M. velifer in 

 its large size and dull fur. It is, however, a very distinct animal. 

 Apparently is has no near relatives, the insertion of the wing mem- 

 brane at the ankle joint and the peculiar color pattern of the hairs 

 on the back distinguishing it sharply from all known American 

 species. 



Abnormalities in the number or position of the two minute upper 

 premolars are interesting as indicating the evolutionary tendency 

 in connection with the reduction of the tooth row. Thus in 16067 

 (Field Museum) from Rosiclare, 111., these two teeth are so placed 

 that instead of standing in the tooth row, the smaller {j)^) on each 

 side is drawn inward while the anterior tooth practically fills the 

 entire space between the canine and p* so that the smaller tooth is 

 hardly visible in side view. 



Specimens of Myotic grisescens were collected in late June 1892, 

 at Marble Cave, Mo., by Vernon Bailey, and were referred by Miller 

 (1897) to Myotis velifer. Of three individuals taken, "one was 

 caught in the cave 150 feet below the surface of the earth ; the others 

 were shot as they came out of the mouth of the cave in the evening " 

 (Bailey, 1905). The true characters of the animal were detected by 

 Howell, in the series of specimens which he secured in Nickajack 

 Cave on August 31, 1908. 



External measurements of Myotis grisescens 



