half grown cat, to that of a half grown mouse.

Of this numerous family only three genera, of modern authors, inhabit
the United States, viz. RHINOPOMA, VESPERTILIO, and TAPHOZOUS. Seven
species, exclusive of the present, are all that have been hitherto
discovered in North America.

We propose to dedicate this new species, to our valuable friend the
justly celebrated naturalist J.J. AUDUBON, as a small tribute of
respect to his eminent talents, and the highly important services he
has rendered science. The drawing which accompanies this paper, is
from his inimitable pencil.

This species was first observed, during the summer of 1829, when an
individual female flew into the apartment of the late Dr. Hammersly,
then one of the resident physicians of the Pennsylvania hospital: on
the subsequent evening a male individual, of the same species, was
also taken in the same manner. In August 1830, a very fine specimen
was brought to the Academy of Natural Sciences, and Mr. Audubon informs
me that the species has very recently been observed in New York.

The natural characters of the species are--General colour black,
sprinkled with gray above and beneath; ears black and naked; auriculum,
short and broad or obtusely triangular; interfemoral membrane, sparsely
hairy; last joint of the tail free: two incisors, with notched crowns,
on each side of the canine teeth of the upper jaw, with a broad
intervening space without teeth.

The dimensions are.--Total length 3 inches 7 tenths; tail 1.7; length
of ear 0.5. breadth of ear 0.4; length of leg 1.7; spread of wings