A MONOGRAPH OF THE BATS OF NORTH AMERICA. 11 



type t^een iu most of the riiyllostoniidie as exemplitied in this memoir 

 iu Artibeus and Macrotus. Tlie nostrils may remain simple with the upper 

 border advanced upon lumen of the o])ening' so as to divide it into two 

 cornua as in most Vesj)ertilionid;e or the himen may be oval as iu Eu- 

 derma. 



In all the genera iu which the foliations about the nostrils are well 

 developed the outgrowths occur in positions of structures which can be 

 named in the muzzles of other mammals. Thus in Ehinolophus (and at 

 least in Hipposidtros, so far as examined) the upper or inner margin of 

 each nostril leads to the development of a fold (supra-narial) which by 

 uniting- with its fellow forms the anterior of the two ascending leaflets 

 or the sella; the lower or outer margin leads to the development of the 

 lateral fold (infra-narial), which passes back to form the lateral margin 

 of the posterior ascending leaflet or the terminal leaflet; the muzzle 

 glands are continuous i)osteriorly, with a short skin-fold which joins 

 with the lateral fold to form the terminal leaflet. The supra-narial also 

 joins the terminal leaflet from in front. The three x)lications end on 

 the terminal leaflet at the part M^here it frees itself from the head. Va- 

 rious supplemental folds occur in Hipposideros^ none of which, however, 

 disturb the xdan. The scheme described for Artibeus is essentially the 

 same, excepting in the fact that a single ascending leaflet is formed, to 

 which both supra narial and infra-narial folds contribute. In Ecto- 

 phylla the entire muzzle-gland series becomes foliate, thus exhibiting 

 a complete development of a tendency announced in Rhinolopkus. In 

 Nycteris the supra and infra narial s do not assist in forming a median 

 structure, but remain well out on the side of the face. 



The lower lip is firmly held to the gum of the lower incisor teeth, as 

 in Vespertilio, or it is free and forms a protrusile, membranous fold 

 as in Atalapha. It maybe entire or divided in the center so as to form 

 two chin plates as in Macrotus and, as a variation, in Xycticejus. In 

 AtaJapha a distinct lappet extends entirely across the chin and iu de- 

 grees of development distinguishes the sexes. The chin itself and the 

 space directly back of it is adorned with scattered warts in all forms, 

 but in rjiyUostouiida', as shown in Artibeus, the entire chin is conspicu- 

 ously adorned with verrucse arranged iu median and lateral groups. 

 In Chilonycteris and Mormops these are the sites of curiously complex 

 leaflets. 



The sides of the face are furnished with skin-folds of various lengths, 

 which are continuous with the external border of the auricle, or a large 

 wart lies directly back of or below the angle of the mouth, while the 

 sides of the muzzle are apt to be more or less thickened by swollen 

 gland-masses, which tend to embrace the side of the nose-leaf as in 

 Artibeus and Macrotus, or ascend toward the vertex of the l^ice, where 

 they either approach each otluM- on the top of the muzzle as in Antro- 

 zousj or end free as in Corynorhinu.s. 



