MAMMALS OF MINNESOTA. 27 
GEeNuS NYCTICEJUS, Rar. 
This genus is defined as follows by Dr. Harrison Allen: 
Head short, broad, flat; ears small, simple, widely separated; 
upper incisors two; membranes naked. 
Skull intermediate between that of Scotophilus and Lasiurus, 
fiat, but not to the extent seen in the former; cranium inflated, 
but not so much as in the latter. It is not elevated; the occip- 
ital elevation is not abrupt compared with that of L. novebora- 
censis, a bat of nearly the same size, it is longer, and the face 
more pointed. The palate is more level and does not slope so 
much as its posterior part. The infra-orbital foramen is larger, 
with a slight tendency toward the formation of a groove. The 
lower jaw is less abrupt; the incisors are placed more ante- 
riorly to the canines in a larger arc. 
Dentition—incisors 4, canines }, molars 4x 2=30. Upper jaw: 
Incisors small, contiguous to canines, and slightly converging; 
canines large, simple. Molars not peculiar. The first more 
slender and longer than the others, but not so broad, destitute 
of the W-shaped crown. 
Lower jaw: Incisors not crowded, bifid. Canine simple. 
turned markedly backward; basal ridge anteriorly well devel- 
oped; first premolar larger than the same tooth in Lasiurus, 
but in comparison with the second is of itself small. The sec- 
ond premolar, if produced, would touch an extended line from 
the canine. The basal ridges of both these teeth are large. 
Molars not peculiar. 
Nycticejus ecrepuscularis LEC., sp. 
TWILIGHT BAT: 
Vespertilio crepuscularis LECONTE. Cuv. An. King., 1831; Proc. Acad. Nat. 
Sci. vii, 1855. 
Vespertilio creeks FR. CUVIER. Nouv. Ann. du Mus., 1832. 
Nycticejus humeralis RAFINESQUE. Journ. du Phys., 1819. 
Nycticejus crepuscularis H. ALLEN. Smith. Misc. Coll. vol. vii, 1864. 
Nycticejus crepuscularis DoBSON. Catalogue Chiroptera, 1878. 
Atalapha ( Nycticejus) erepuscularis COUES: SuRY. 100th Mer. Rep. Zool., 1875. 
Color somewhat variable, face black, membranes blackish 
brown, back dark fawn to brown, below lighter, brownish ears 
small, ‘‘internal basal lobe small and curved, external basal 
lobe also rather inconspicuous, between the latter and the angle 
of the mouth a small wart is present,” tragus straight on the 
internal and irregularly convex on outer border. Sides of face 
swollen, chin with a naked space, eyes small with a wart above 
