AMERICAN BATS — ^HANDLE Y 



121 



PLECOTUS ( CORYNORHINUS l 



TOWNSENDII 

 USNM 148550 



PLECOTUS ( PLECOTUS ) AURITUS 

 USNM 86667 



TRANSVERSE 

 RIBS 



BASAL LOBE 



ANTERIOR BASAL 

 LOBE 



ACCESSORY ANTERIOR 

 BASAL LOBE 



CONNECTING 

 MEMBRANE 



PLECOTUS ( IDIONYCTERIS l 



PHYLLOTIS 

 AMNK 62260 

 MCZ 5943 



Figure 9. — Variation in the auricle and its appendages in Plecotus. Free-hand sketches. 



have been derived very early and had a long subsequent period of in- 

 dependent development and specialization. 



Systematic Treatment 

 Key to the genera Euderma and Plecotus 



Posterior basal lobe of auricle attached to base of tragus; auditory bulla elongated 

 (elliptical in outline); P almost as small as P; hypocone cusp indicated on M* 

 and M2; lower canine small, but its anterointernal cusp greatly enlarged; P| 

 absent; P* with well defined metaconid cusp; coloration black and white in 

 bold pattern Euderma (p. 122) 



Posterior basal lobe of auricle separated from tragus by a notch; auditory bulla 

 not elongated (circular in outline); I* a third higher and twice as wide as P; 

 hypocone cusp not indicated on M' and M^; lower canine large, but its antero- 

 internal cusp small; Ps present; P4 lacking metaconid cusp; coloration drab 

 brownish, essentially without pattern Plecotus (p. 127) 



