A MONOGRAPH OF TFIE BATS OP NORTH AMERICA. 119 



Kotoon Adelonycteri^ aerotinus. — Dobson (?. c.) includes A.fuseusimder 

 A. serotin us Sclireb. In Ids judfiiiKMit it should constitute but a variety 

 of the Old World species. " It difiers." says this observer, " from Euro- 

 pean forms of V. seroiinus and from those from Central America in be- 

 ing- smaller, the forearm apparently never exceeding 1".8 and the foot 

 0".4; also in the somewhat deeper emargination in theupper half of the 

 outer margin of the ear." He follows these remarks with a table of 

 measurements of specimens from ]^orth America and Cuba. C. Hart 

 INIerriam (Mammals of the Adirondack Eegion, 1886), follows Dobsou 

 and designates ^4. fuscus, under the rules of the JSTuttall Ornithological 

 Ckib, as a geographi(!al variety, viz, the T". serotinus fuscus. I have 

 examined two adults and three immature specimens of A. serotinus 

 (National Museum) in the i)reparation of this revision, and hold to the 

 oi^inion expressed in the ^Monograph of 1804, that it is distinct from A. 

 fuscus. 



In this connection the following description of A. serotinus is pre- 

 sented : 



Hair everywhere, both on dorsum and venter, nearly unicolored ; the 

 base and greater part of the shaft is of a dull brown, the tips slightly 

 lighter. The light shade is more marked on the venter than on the 

 dorsum. The young are nuich lighter, and present a distinctly pallid 

 appearance everywhere. The color of the tips of the hair of the dorsum 

 is lighter than that of the shafts. 



The hair on the membranes in both adult and young as in A./uscus^ 

 except that a sparse growth of pallid hair extends on dorsum of the in- 

 terfemoral membrane between the tail vertebrse and the thigh. This 

 space is naked in A. fuscus. 



Skull. — The lachrynnil swelling on the orbit is convex; seen from 

 above it is much more prominent than in A. fuscus, while the process 

 over the lachrymal is much less trenchant. The sagittal crest at the 

 occiput is stouter. A conspicuous groove lies on maxilla between the 

 swelling over the roots of the canines and incisors. 



Teeth. — The lateral maxillary incisor is convex on outer border in- 

 stead of being concave. I have seen but one exception to this in A. 

 serotinus; in A. fuscus it is the rule. The median maxillary incisors 

 are sharply inclined toward ea(;h other. The anterior nasal aperture 

 is acuminate above. The lower incisors are more crowded than in A. 

 fuscus; the outer tooth is in contact with the canine by a broad surface. 

 The hypocone of the last molar is quadrate. 



In A. fuscus the palatal ruga' are seven in nund)er. The fust lies 

 directly back of the incisors and is entire. The second and third are 

 simple, and as a rule lie straight across the palate and are arranged in 

 double crescents at irregular intervals, i. e., the spaces between them 

 are equal. Jn A. serotinus the ]>alatal ruga* are also seven in number. 

 The lirst is interrupted in the center. The second is sinuate instead of 

 straight as in A. /j/.scMs. The remaining are arranged in crescents at 



