XVlll INTEODtrCTION. 



tegument of the nostrils, partly of highly differentiated gland struc- 

 tures; and investigation of their minute structure confirms this 

 deduction*. 



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

 lopTiidce, in which the nasal appendages reach their highest develop- 

 ment, the superior maxillary division of the fifth nerve is of remark- 

 ably large calibre, as, indeed, the size of the infraorbital foramen 

 shows. The nasal branch of this nerve, which is given off immedi- 

 ately 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 superior maxillary bone, but soon spreads out into numerous 

 filaments, which pass into the muscles and integument above and 

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

 further considerably augmented by the large nasal branch of the 

 ophthalmic division of the fifth nerve f. 



While the many foliations, elevations, and depressions which 

 vary the form of the nose-leaf also greatly increase the sensory 

 surface so abundantly supplied by the fifth nerve and in rapid 

 fiight intensify the vibrations conveyed to it, the great number 

 of sweat- and oil-glands which enter into its structure perform an 

 important function, analogous to that of the glands of the aiiditory 

 canal in relation to the memhrana tympani, in maintaining its sur- 

 face in a soft and highly sensitive condition. 



The nasal appendages of Chiroptera, then, may 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 sensory 

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



* The minute anatomy of the nasal appendages of Shinohphus hipposideros 

 (as regards their cutaneous, muscular, and glandular structures) has been well 

 worked out by Dr. Eedtel (Zeitschr. fiir wissennh. Zool. 1873, pp. 254-288, 

 pi. xiv.), who describes the extraordinary richness of these parts in glands, 

 which he divides into two classes — " Talgdriisen " and " Schweissdriieen." He 

 hazards, however, no opinion as to their mode of origin or functions. 



t In the Shinolophidcs and Nycterid<s, owing to the position of the nasal ori- 

 fices, which open so far back on the muzzle, the cup-shaped depression in which 

 they are placed evidently corresponds to the anterior part of the nasal fossse, 

 which in other animals is divided by a cartilaginous septum, covered in by in- 

 tegument, and supplied by the nasal branch of the ophthalmic division of the 

 fifth nerve ; so that here we find this highly sensitive portion of the nose freely 

 exposed to the air, and undoubtedly constituting, in addition to the surround- 

 ing nasal appendages, an exquisitely sensitive organ of touch. 



