646 CHIROPTERA 



muzzle, but also in the highly sensitive and widely extended integu- 

 mentary structures entering into the formation of the wing-mem- 

 branes and ear-conchs; while in many other species, notably in the 

 tropical Rhinolophine and Phyllostomatine Bats, peculiar foliaceous 

 cutaneous expansions surrounding the nasal apertures or extending 

 backwards behind them are added. These structures, collectively 

 known as the "nose-leaf" (whence the term "leaf-nosed Bats"), 

 have been shown by Dr. Dobson to be made up partly of the 

 extended and thickened marginal integument of the nostrils, and 

 partly of the highly differentiated glandular eminences occupying 

 the sides of the muzzle, in which, in all the common Bats, the 

 vibrissse are implanted. 



In all species of leaf-nosed Bats, and especially in the Rhino- 

 lophidce, where the nasal appendages reach their highest development, 

 the superior maxillary division of the fifth nerve is of remarkably 

 large calibre. The nasal branch of this nerve, which is given off 

 immediately beyond the infraorbital foramen, is by far the largest 

 portion ; the palpebral and labial branches consisting of a few 

 slender nerve-fibres only. This branch passes forwards and upwards 

 on the side of the maxilla, but soon spreads out into numerous 

 filaments extending into the muscles and integument above, and 

 into the base of the nose-leaf. The nerve supply of the nose-leaf is 

 further augmented by the large nasal branch of the ophthalmic 

 division of the fifth nerve. While the many foliations, elevations, 

 and depressions which vary the form of the nose-leaf greatly increase 

 the sensory surface supplied by the fifth nerve, and during rapid 

 flight intensify the vibrations conveyed to it, the great number of 

 sweat and oil glands which enter into its structure perform a func- 

 tion analogous to that of the glands of the auditory canal in relation 

 to the membrana tympani in maintaining its surface in a highly 

 sensitive condition. The nasal appendages of the Chiroptera may 

 thus be regarded as performing the office of an organ of a very 

 exalted sense of touch standing in the same relation to the nasal 

 branches of the fifth nerve as the aural apparatus to the auditory 

 nerve ; for, as the latter organ collects and transmits the waves of 

 sound, so the former receives impressions arising from vibrations 

 communicated to the air by approaching objects. 



In no order of mammals is the ear-conch so greatly .developed or 

 so variable in form. Thus in most of the insectivorous species the 

 ears are longer than the head, while in some, as in the common 

 Long-eared Bat (Plecotus auritus), their length nearly equals that of 

 the head and body. The form of the conch is very characteristic of 

 the various families ; in most the tragus is remarkably large, in 

 some extending nearly to the outer margin of the conch ; and its 

 function appears to be to cause undulations in the waves of sound, 

 and so intensify and prolong them. It is worthy of notice that in 



