AMEKICAN BATS OF THE GENEEA MYOTIS AND PIZONYX 133 



meet to form a sharp ridge. ^® Correlated with this difference is 

 the more tapering front end of the brain case, a slightly narrower 

 interorbital constriction (3.5 to 3.9 mm. instead of 4.0 to 4.4 mm.) 

 with more graceful lines; and a slightly larger rostrum as com- 

 pared with the brain case, features which are obvious to the eye, 

 and consistently borne out by actual measurements. The length 

 of the maxillary tooth row is essentially the same as in Myotia 

 lucifugus (usually 5.2 to 5.6 mm.), but the maxillary breadth at m^ 

 is distinctly less (usually 5.3 to 5.8 mm. instead of 5.5 to 6.1). • These 

 cranial differences between the two species become obvious on com- 

 parison of the tables of measurements pages 134 and 135. 



Teeth. — The teeth are so similar to those of Myotis liwifugus 

 lucifugus that we have been unable to detect any positive characters 

 by which they may be recognized. Apparently the two small upper 

 premolars tend to be more nearly equal in area when seen in crown 

 view, but this feature is not constant. The cingulum and the secon- 

 dary cusps and ridges are developed as in M. lucifugus. In a speci- 

 men from Arkansas (No. 5831 F. M.) the second upper premolar is 

 absent on both sides. 



Measurements. — For measurements see tables, pages 134 and 135. 



Specimiens exmnined. — Total number 443, from the following 

 localities : 



ALABAMA: Anniston, 1 ale. (M. C. Z.). 

 ARKANSAS: Greenway, 2 skins (F. M.). 

 ILLINOIS: Rosiclare, 6 skins, 4 ale. (F. M.) ; no exaet locality, 1 ale. 



(U.S.N.M.). 

 INDIANA: Bicknell, 1 ale. (U.S.N.M.) ; Wheatland, 3 ale. (U.S.N.M.) ; 



Wyandotte Cave, 3 ale. (U.S.N.M.), 14 skins, 3 ale. (F. M.), 10 skins. 



including type, (M. C. Z.). 

 KENTUCKY: Mammoth Cave, 269 ale. (U.S.N.M.), 6 ale. (A. N. S. P.), 



1 ale. (B. M.). 20 ale. (M. C. Z.). 

 MICHIGAN: Grosse Isle, 1 skin (U.S.N.M.), 

 NORTH CAROLINA: Roan Mountain, 1 ale. (U.S.N.M.). 

 PENNSYLVANIA: Center County, (cave), 2 skins, 25 ale. (U.S.N.M.). 

 TENNESSEE: Hickman Co., 1 skin (A. M. N. H.). 

 VERMONT: Brandon, 2 skins, 9 mummie.s (U.S.N.M.) ; Proctor, 21 skins. 



37 ale. (U.S.N.M.). 



Remarks. — That Myotis sodalis has been so long overlooked is due 

 no doubt to the general resemblance which the animal bears to 

 Myotis lucifugus^ with which species the specimens of it in museums 

 have generally been confused; when once its characters are recog- 

 nized, however, there is no doubt as to its identity. Not only is the 

 tricolor fur, with the characteristic pinkish-gray tinge distinctive, 

 but the slightly smaller size of the foot and the normal presence 

 of an obvious keel on the edge of the calcar are further diagnostic. 



" In 20 skulls of Myotis sodalis from Mammotli Cave the sagittal crest is present eighteen 

 times, while in 20 skulls of M. lucifugus lucifugus it is present only three times and then 

 much less well developed than in the average of the other species. 



