IXTRODUCTIOU. vii 



families ; thus Phyllostoma hastutum has 13 thoracic vertebrse, 

 while Artiheus perspicillaius has 12. The cervical vertebrse are 

 very broad, but short from before backwards. With the exception 

 of the axis none of the cervical or thoracic vertebrae develop spinous 

 processes, a characteristic feature in the osteology of the Order. 

 From the first thoracic to the last lumbar vertebra the spinal column 

 forms a single curve backwards, which is most pronounced in the 

 lumbar region. The bodies of the vertebrae are very slightly mov- 

 able upon each other, and in many old individuals appear to become 

 partially anchylosed together. The caudal vertebras are simple 

 cylindrical bones without processes, and their number and length 

 is extremely variable even in closely allied species ; the anterior 

 vertebrae are generally united to the tuberosities of the ischia. In all 

 species of Megachiroptera (except in the very aberrant form Notopteris 

 macdonaldii) the tail is very short or absent ; in Pteropus, in some 

 species of Epomophorus, and in Melonycteris there are no caudal 

 vertebrae extending beyond the tuber ischii. In the Microchiroptera 

 the tail reaches its greatest development in the Vespertilionine 

 alliance *, in some genera of Vespertilionidce (as in Kerivoula, Nata- 

 lus, and Miniopfenis) exceeding the length of the head and body, 

 but the vertebrae rarely exceed 9 in number ; in Nycteridce the 

 caudal vertebrae are very long in the genus Nycteris, very short and 

 concealed in the base of the interfemoral membrane in Megaderma. 

 In the Emballonurine alliance the tail is alone well developed in 

 the Mohssi, in Bhinopoma, and in some of the insectivorous species 

 of Phyllostomidce ; in most of the genera of GlossopJiagce, in all the 

 frugivorous Stenodermata, and in the sanguivorous Desmodontes it is 

 externally invisible or altogether absent. This shows that the develop- 

 ment of the tail is correlated to the habits of the different species f. 

 In all Bats the presternum has a prominent keel for the attach- 

 ment of the anterior portion of the great pectoral muscle; the meso- 

 sternum has a slightly prominent keel in most species of Micro- 

 chiroptera, which reaches its greatest development in the Ehino- 

 lophidce, especially in the genus Tricenops, where it is nearly as 

 deep as that of the presternum J; the xiphisternum is moderately 



* For definitions of the two alliances into which I have divided the families 

 of Microchiroptera see Ann. & Mag. Nat. Hist. xvi. p. 347 (1875), or Monogr. 

 Asiat. Ohiropt. pp. 7, 8 (1876). 



t For remarks on the development of the interfemoral membrane, see infrdt, 

 p. xxviii. 



t See my paper " On the Osteology of Tricenops persicus,'' and accompanying 

 plate, in Journ. Asiat. Soo.Beng. xli. pp. 136-142, pi. vi. fig. S (1872). 



b2 



