NYCTINOMUS TENTHS. 
of which the lengthened nasal tubes are bent and pressed to such a degree, that 
the communication from without, between the nasal fossae, is suspended. The 
transparent membrane of the anterior extremities is as in the genus Noctilio, 
which the Nyctinomi also resemble by the hare-lip. The hind feet are covered with 
hair, of such length as to extend beyond the claws. It is remarkable that this 
circumstance should be placed necessarily in the number of the generic characters of 
this small group : it is observed among the Nyctinomi alone, and it is found in all 
of them. The tail presents a form which is as yet new : it is almost as long as hi 
the genus Vespertilio, but it has a portion only enveloped in the interfemoral 
membrane, Tliis membrane is smaller than in the last-mentioned genus, but it is 
thicker^ and supported, or rather drawn inward, by strong muscular fibres. It forms 
a sack by means of natural folds, in consequence of the membrane of the wings 
passing over the carpus, to unite itself without interruption to the interfemoral 
membrane. 
Mr. GeofFroy enumerates three species of Nyctinomi : the first was discovered 
by himself in Egypt ; the second is described by Dr. Buchanan (Hamilton) in 
the Vth Volume of the Transactions of the Linnean Society, with the name of 
Vespertilio plicatus ; the third was found by Commerson in Mauritius, and was 
described from his materials by Herman, in his Obscrvationes Zoologies!, page 19, 
with the name of Vespertilio acetabulosus. The first is named by M. Geoffrey, 
Nyctinome d'Egypte ; the second, Nyctinome du Bengal ; and the third Nyctinome 
de Port-Louis. 
A fourth species of this genus, the Nyctinomus tenuis, was discovered by me in 
Java ; and in the following description, the characters which it has in common 
with the other Nyctinomi, and the peculiarities which characterize it as a species, 
will be detailed. The ears are of excessive size, and in a great measure conceal 
the head : their form is irregularly oblong, and they are surrounded by a membra- 
naceous margin, united on the crown of the head, from which they stretch forward 
so as completely to cover the forehead. At the lower extremity of the auricle a 
rounded obtuse lobe, formed as in several other genera of this order, by the 
enlargement of the tragus, covers the meatus auditorius. The skull is considerably 
compressed. The eyes are extremely minute, almost concealed from view, and 
covered by the lower fold of the membranaceous border of the ear. The upper lip 
is very fleshy, marked with seven or eight large transverse folds, and passes forward 
to unite itself with the nose, which is large, surrounded by a delicately crenated 
margin, and deeply emarginate at the extremity. The nostrils are circular, obscure, 
and placed at the extremity of the nose. The lips and lateral parts of the face are 
