A MONOGRAPH OK THE BATS OF NORTH AMERICA. 



61 



The above diagnosis may be compared with advantage with that of 

 Corynorhinus and Plccotus. 



Cori/norhinus. — Thri'c premolars in lower j.aw. Auriclo not constricted at base; 

 both basal ridges being free from tragus. Internal basal ridge with thick trans^■er8e 

 fold simulating an internal basal lobe which is absent. Width of internal hem 

 nearly half that of the auricle. Tragus with dehnetl external basal lobe and notch. 

 External base lobe with internal lobule ending in large post rictal wart. C'lavate 

 process on each side of the snout; nostrils with raised border, lumen sinuate. 



riccutas. — Three premolars in each jaw. Auricle not constricted at base. The 

 narrow internal auricular hem not over one-eighth width of the auricle and is pro- 

 duced inferiorly into a lappet. Internal basal ridge simple, free from tragus. Ex- 

 ternal basal lobe not limited posteriorly and bears a minute lobule on inner surface. 

 Tragus with well-defined notch and basal lobe; post rictal wart hairy, conjoined to 

 basal lobe. 



The following statements concerning the differential characters of 

 JEuderma, Corynorhinus, Plecotus, and tSynotus are herewith submitted. 

 In my judgment Synotus is more widely separated from the other three 

 genera than are any of the last named from one another, and it is prob- 

 ably true that Synotus is not a member of the group of the plecotian 

 bats, but is in closer affinity with Vesperugo. 



Eiiderma. 



Internal basal lobe free 

 crossing internal ridge. 



Both internal and exter- 

 nal ridges continuous 

 with base of tragus. 



Tragus witliout internal 

 basal lobe. 



Terminal cartilage, 

 fcurth digit axial. 



Coronoid process round- 

 ed; angle to lower jaw, 

 broad at ba>se. 



Tympanic bulla extends 

 forward to point op|>o- 

 8it(i middle of glenoid 

 cavity. Spheno-i>ala- 

 tine toraraen present; 

 the upper orbital bor- 

 der rugose. 



Palatal plate extends 

 back of line of last 

 molar for a distance 

 ei]ualling nearly one- 

 halt the length of the 

 ptervuciii process. 



Anterior teiiii>oral crest 

 not marked. 



Second upi)er premolar 

 not touching first mo- 

 lar. 



Corynorhinus. 



Internal basal lobe not 

 free, rudimentary. 

 Large swollen thread 

 across internal riuge. 



Ridues not continuous 

 with base of tragus. 



Tragus with internal 



bas;il lobe. 

 Teiininal cartilage 



fburtli digit axial. 



Coronoid process acumi- 

 nate; angle to lower 

 .jaw not broad at base. 



Tymi)aui(' bulla reaches 

 posterior border of 

 glenoid cavity. 

 Spheuo-palaline ])j-es- 

 ent; the up])erorbital 

 border not rugose. 



Plecotus. 



Synotus. 



Internal basal lobe 

 free, not crossing 

 internal ridge. 



Ridges not continu- 

 ous with base o f 

 tragus. 



Tragus with internal 

 bas;il lobe. 



Terminal cartilage 

 fourth digit axial. 



Same . 



T y m panic bulla 

 r e a c h e s a point 

 slightly in advance 

 of till' glenoid cavity. 

 Sphenopalatine for- 

 amen apparently ab- 

 sent ; rpjier orbital 

 l)order not rugose; 

 trenchant. 



Anterior temporal crest 

 not marked. 



Second upper premolar 

 not tonching first 

 molar. 



Sagittal and anterior 



temporal crests 



marked. 

 Second upjier j)remo- 



lar not touching first 



molar. 



No internal basal lobe. 



Ridges not continuoub 

 with base of tragus. 



Tragus with interna, 

 basal lobe. 



Terminal cartilage 

 fourth digit defiocted 

 toward thumb. 



Angle of lower .jaw nar- 

 row at base; coronoid 

 process i)ointed. 



Tympanic bulla reaches 

 posterior border of glen- 

 oid cavity. Splieno- 

 palatine foramen i)res- 

 ent; theupj)er orbital 

 border not rugose. 



Palatal plate extends 

 back of line of last mo- 

 lar for adistanceeqiuil- 

 ling one-third the 

 length of pterygoid 

 process. 



Sagit inland ;interi()r tem- 

 poral crest8 marked. 



1. Euderma maculata (J. A. Allen). 



Histiotus maculaius J. A. Allen, Bull. Anier. Mus. Xat. Hist., III. 1891. 



Diagnosis. — The diagnosis of the siingle species is that of the genus. 



Description.— Eiirs three-fourths length of the forciirm, broad at tij), 



united by a small membrane. Internal basal lobe well detined. Inter' 



