CHEIROMELES TORQUATUS. 
position. The auricle is very broad at the base, and extends along the skull from 
the eyes towards the neck : posteriorly it forms a curve, which rises again to a large 
tragus, placed exteriorly below the auricle. It is about two lines long, semicordate, 
obtuse, and continued anteriorly into a small membranaceous border, extending 
towards the angle of the mouth. The auricle itself is oblong, nearly obtuse, simple 
at the anterior, and involute at the posterior margin. The general direction of the 
ears is upward and outward. The base of the auricle leads to a tube of great trans- 
verse dimensions. Indeed, the great extent of the internal ear is one of the peculiarities 
of Cheiromeles. The diameter of the entrance to the cavity of the tympanum is 
likewise of extraordinary size : in preparing the skull, the bones of the ear were easily 
separated for examination, and, in comparison with those of the human ear, were 
found of enormous dimensions. In the skull all the parts belonging to the ear are 
greatly developed, and the cochlea in particular is of uncommon extent. The texture 
of the os petrosum was apparently very loose. 
The eyes are small, and partially concealed. The eyelids are surrounded by a 
minute circle of rigid hairs, regularly disposed. The anterior margin of the auricle 
is adapted to afford a partial covering and protection to the eyes. The front teeth in 
the upper jaw resemble a section of a cone through the axis : they are of great strength ; 
those in the lower jaw are comparatively small. The canine teeth above have a sharp 
edge along their internal angle, but in other respects these teeth are of moderate size, 
and of simple structure. The large grinders agree in all essential points with those 
of Nyctinomus ; but this agreement will be shewn more fully in the comparison of 
Cheiromeles with that genus. 
Of all the Vespertilionidae with which I am acquainted, the Cheiromeles torqua- 
tus has, next to the Nyctinomi, the greatest extent of wing. The phalanges of 
the third and fourth fingers are remarkably long and delicate. Our animal possesses a 
peculiarity of structure at the union of the arm with the body, similar to that which 
lias already been observed, in different degrees of development, in several Vesper- 
tilionida?. It consists of a deep cavity, extending from the axilla and neighbouring 
parts, towards the spine and the hypochondriac Anteriorly it is bounded by a 
membrane extending from the arm to the pectoral muscle, and then passing to the 
sides of the body, and uniting with the common integuments : the expanded mem- 
brane of the arms and body is its posterior limit. The cavity thus formed is about an 
inch deep, and nearly two inches long ; it is lined with a very delicate membrane, 
and its uses will be pointed out in the sequel, A structure analogous to this occurs 
in the Pteropus palliatus of Geoffroy, and in the genus Cephalotes. In the Saccopteryx 
