6. vEspEBtreo. 183 



6. VESPERUGO. 



Vesperugo, Keys. ^ Bias. Wiegm. Archiv, 1839, p. 312; Fauna 

 Beutschl. p. 49 (1857). 



Muzzle generally very broad and obtuse, the glandular prominences 

 between the eyes and the nostrils well developed, increasing the 

 width of the face ; crown of the head flat, or very slightly raised 

 above the face-line; nostrils opening sublaterally by simple cres- 

 centic apertures on the front surface of the naked extremity of the 

 muzzle ; ears separate, generally much shorter than the head, broad 

 and triangular, the outer margin extending forwards beyond the 

 base of the tragus, the internal basal lobe rounded ; tragus generally 

 short and obtuse, the outer margin more or less convex, the inner 

 margin straight or concave. TaU less than the length of the head 

 and body ; the calcaneum generally supports on its posterior margin 

 a small rounded cutaneoxis lobe {the postcalameal lobe), which, in 

 this genus and in the closely allied genus Chalinolobus, reaches its 

 greatest development ; feet short and broad ; membranes thin. 



Dentition. Inc. ^^, in the subgenera Scotozous and Rhogeessa 

 i^; pm. 1^, or g^, or (in the subgenus Lasionycteris only) 

 3^' Upper incisors in pairs separated by a wide interval; the 

 outer upper incisors on each side parallel, and close to the longer 

 inner one, often minute, rarely absent ; first upper premolar minute 

 or absent ; first lower premolar in the tooth-row, not crushed in 

 between the adjoining teeth ; its summit directed slightly outwards. 



The Bats of this genus are generally easUy distinguished by their 

 comparatively thickly formed bodies, by their flat broad heads and 

 obtuse muzzles, the thickness of which is iacreased in front by the 

 rounded glandular elevations, by their short, broad, and triangular, 

 obtusely pointed ears, by their obtuse and usually sUghtly incurved 

 tragus, by their short legs, and by the presence in most species of a 

 well developed postcalcaneal lobule (see Plate XIII. fig. 1). This 

 lobule (which is supported by a cartilaginous process derived from 

 the calcaneum) probably acts as a kind of adhesive disk in securing 

 the animal's grasp when climbing over smooth surfaces. 



Some of the species, however, in their external form closely 

 resemble those of other genera, while others, although corresponding 

 with the typical forms of the genus in general external structure, 

 yet differ in the number of their teeth. Thus V. ( Vesperus) velatus 

 resembles Plecotus auritus so very closely in the form of the ear- 

 conch and tragus that it has been made the type of a genua 

 Eistiotus by Gervais; and V. annectens agrees so remarkably in 

 general form with the species of Vespertilio that it can only be 

 distinguished by its dental characters ; while F. (Rhogeessa) parvulus 

 and F. (Scotozous) dormeri correspond rather with the genera 

 Nycticejus and Scotophilus in dentition, although they evidently 

 belong in their aggregate characters to this genus. 



This genus probably contains the greatest number of individuals 



