INXKODTCTION. Xxix 



6. 'Wing-pouches (Saccopteryx, p. 369). 



The form and relative development of these structures in male 

 and female will be found described under the head of each species 

 in which they occur. 



Among the Microchiroptera the odoriferous secretions of these 

 glandular organs appear to act principally in bringing the sexes 

 together in the dark retreats in which they hide, as they are always 

 found most abundant during the rutting-season ; but in the large 

 species of Megachiroptera, as in Pteropus, which roost in trees ex- 

 posed to the attacks of passing enemies, and in which they are also 

 developed in the female, but to a less extent, the strong musky 

 odour exhaled, and which fills the air in the neighbourhood of their 

 haunts, is evidently protective. (See also my paper " On Secondary 

 Sexual Characters in Chiroptera," P. Z. S. 1873, pp. 241-252.) 



Geneeative Oegans. 



The penis is pendulous in aU Bats, and in many species provided 

 with a well-developed bone. Its form varies sometimes considerably 

 even in species of the same genus. Thus in JRhinolophus luctus the 

 glans penis is very large and cylindrical, and the urethra opens on 

 the upper surface at a distance of more than 0-2 inch from its distal 

 extremity, to which it extends forwards in an open groove ; in most 

 other species of the genus the urethra opens at or near the ex- 

 tremity of the glans ; also in Yesperugo, in the species of the sub- 

 genus Hesperoptenus the form of the penis (described at p. 241) is 

 quite different from that of other species of the genus. In Vespe- 

 rugo noctula and in Seotophilus pallidiis there is a long and slender 

 bone. In Noctilio the glans is long and conical, and the urethra 

 opens on its upper surface about O'l inch behind the conical extre- 

 mity, the orifice guarded above by a small fleshy process, from which 

 a groove runs backwards to the point of attachment of the prepuce. 



In most species of Microchiroptera the prepuce projects consider- 

 ably beyond the glans, and its great development in Vesperugo 

 ahramus is characteristic of that species (see p. 227). 



In Megachiroptera, with few exceptions, the species have a broad 

 spatulate bone in the glans penis. This is especially well developed 

 in the genus Pteropus, in which it appears to form the greater part 

 of the glans. In Eonycteris, although the glans seems fleshy, there 

 is a broad bone concealed within, and the opening of the urethra is 

 triangular. In Harpyia the penis bone is slender, more like that 

 in some of the Microchiroptera. 



