AMERICAN BATS OF THE GENERA MYOTIS AND PIZONYX 55 



the other races (present in both of the known specimens) ; molari- 

 form teeth, both above and below, enlarged, so that the distance 

 between the canine and pm^ is reduced, and a noticeable crowding 

 of the two small premolars takes place. 



Color. — The type, after long immersion in alcohol shows such 

 obvious indications of fading that its color can not be regarded as 

 normal. It resembles that of similarly faded old specimens! of 

 Myotis lucifugus lucifugus. The second specimen, a skin from Fort 

 Hancock, Tex., is not distinguishable from the less glossy individuals 

 of the northeastern race. 



Skull. — The skull does not differ from that of Myotis lucifugus 

 lucifugus except that the presence of the sagittal crest in the two 

 known specimens is an indication that this ridge is more usually well 

 developed than in the northern races. 



Teeth. — The teeth resemble those of the typical race in form, but 

 the size of the molars and large premolar is obviously increased. In 

 the type specimen the crown of m ^ measures 1.40 by 1.85 mm. ; in 

 the Fort Hancock specimen it is slightly larger, 1.45 by 1.85 mm. 

 The corresponding measurements in Myotis lucifugus lucifugus and 

 M. I. carissima are usually 1.20 to 1.35 by 1.50 to l.TO. While the 

 increase in size of the individual cheek teeth does not produce a 

 lengthening of the entire tooth row as measured from front of canine 

 to back of last molar (see tables of measurements), it increases the 

 distance from front of pm * to back of m ^ as compared with the other 

 races of M. lucifugus., with the result that the space occupied by the 

 two small premolars between the canine and the large premolar is 

 shortened. In this reduced space only one small tooth is visible 

 when the maxillary series is viewed from the side. This crowding 

 is so great in the type specimen that the posterior small tooth has 

 been eliminated. 



Measu/retiients. — For measurements see tables, pages 58 and 61. 



Specimens examined. — Total number 2, from the following locali- 

 ties: 



TEXAS: Fort Hancock, El Paso County, 1 &kin (U.S.N.M.). 

 TABASCO: Teapa, 1 ale. (B.M.). 



Remarks. — Although the material is unsatisfactory, the two speci- 

 mens indicate rather clearly the existence of a Mexican race of 

 Myotis lucifugus. This form will probably be found to occur along 

 the border of the United States south of the region occupied by the 

 light-colored, small-toothed subspecies ca7^sirna and phasma. 



The Fort Hancock specimen agrees perfectly with the type in the 

 large size of the molariform teeth as compared with those of the 

 other races of M. lucifugus. Its upper premolars are abnormal in a 

 way that we have never seen in any other bat. The large tooth is 



