A MONOGRAPH OF THK BATS OF NORTH AMERICA. 49 



nasal at the ui)per fifth of its outei- border, the remaining four-fifths 

 being occupied with the preinaxilla. The nasals twice the width above 

 as below, where the free margin is oblique from within outward so that 

 an iuv^erted /^-shaped space is delined between them. Tlie frontals 

 separated by a sharply limited median suture; the encranial and facial 

 region in the orbit defined; a fronto-squamosal suture evident: An 

 intermediate osside to the squamosal and opisthotic elements is seen 

 at the side of the cranium. The basioccipital and exoccipitals unite 

 as in mammalia generally. The part first named is tilted upward, 

 thus forming the wall of a deep basicranial depression. The pro- 

 portions of the tympanic bone and cochlea are as in the adult. The 

 permanent central upper incisors are alone erupted. Five hook-like 

 deciduous teeth are visible. They may be named two incisors, one 

 canine and two premolars. All the permanent lower incisors are erup- 

 ted. The only hook-like deciduous tooth is oue in the position of the 

 canine. The premolars and molars are near the surface of the gum and 

 can be obscurely outlined. 



The glans penis is free. The preijuce is reduced to a conical lappet 

 inferiorly.* 



Maxillary teeth. — Incisors (jontiguous or separated by a slight inter- 

 val. The lateral incisor does not touch the canine tooth. Central 

 incisors with quadrate crown and straight bilobed cutting edge. 

 Lateral incisors subtriangular; crown with concave anterior surface, 

 and oblique, simple, cutting edges. In some individuals these teeth 

 exhibit concave cutting edges and convex lateral borders. The canine 

 is as long as the interval between the two teeth is wide, with low cin- 

 gulum on all sides except the buccal. The first premolar touches both 

 canine and second premolar or slightly overlaps the latter. The second 

 premolar is larger than the first, with rudiment of i)rotocone. Pos- 

 teriorly a double buccal contour is seen, with a rudiment of a metacone. 

 Thegrindingsurfaceof the first molar is elongate, with a slight incli- 

 nation backward; the protocone is conoidal. Between it and the 

 scarcely fluted buccal aspect a smooth, deeply concave surface is seen. 

 With the exception of an irregular double basal contour all trace of 

 the conoidal shape of the paracone and metacone is lost. The inner of 

 the two lines is often incomplete (see figure). The hypocone is conoidal 

 and well developed. On the buccal surface the positions of the para- 

 cone and metacone are well defined, conspicuous, and sectorial. The 

 metacone, which is more especially defined by the inner con^-our, is 

 coarsely pectinate in some specimens. The second molar is smaller than 

 the first. The inner contour line extends the entire length of the buc- 

 cal border. The molars are contiguous at their buccal edge only. This 



*Tho value of this character is api)aront when compared with Sinniira, in which 

 genus the glans is free beneath only — the abruptly truncated prepuce above being 

 adherent almost to the entire upper surface of the glaus. In BrachyphijUa the glan§ 

 is concealed by an elongate prepuce. 



441— JTo. 43 4 



