XVI INTRODTTCTION. 



in which the interfemoral is very large and the tail rudimentary or 

 perforating the membrane and appearing upon its upper surface, as 

 in most of the genera of Emhallonuridce, and in the groups Mor- 

 mopes and Vampyri of Phyllostomidce. 



The first toe is composed of a metacarpal bone, a proximal and an 

 ungual phalanx, and is slightly shorter than the other four toes, 

 which have each an additional phalanx, except in the subfamily 

 Phyllorhinhim and in the anomalous genus Thyroptera, where all 

 the toes have the same number of phalanges as the first toe and are 

 equal to it in length. In the very remarkable genus CJieiromeles 

 the first toe is thumb-like and separated from the others ; in the 

 Molossi the first and fifth toes are much thicker than- the interme- 

 diate toes. 



MuscuLAE System. 



Few striking differences are observable in the muscular system of 

 the Chiroptera. As Dr. Macalister remarks, " a strong family like- 

 ness pervades the entire series ; the differences are chiefly slight, 

 though often suggestive, varieties of detail"*. As the few differences 

 known are of little importance in their bearing on the systematic 

 arrangement of the species, it will be sufficient here to refer to the 

 principal work on the subject, of which the title is given in the foot- 

 note below. 



Neevotjs System. 



Witnout entering upon a general description of the nervous 

 sj'stem in Chiroptera, I purpose, under this head, to consider the 

 chief modifications in the organs of touch and hearing which have 

 so important relations to the systematic arrangement of the species, 

 and which probably reach the highest development among Mammals 

 in this Order. 



In the Rhinolophidce, Nycteridce, and Phyllostomidce peculiar folia- 

 ceous cutaneous expansions surround or extend backwards behind the 

 nasal apertures (see Plates VI., XI., XXX.). In no other species of 

 Mammals have analogous structures been found, and their functions 

 and homologies appear to be imperfectly understood. 



A careful investigation of the structure, relative position, mode of 

 origin, and nervous supply of these processes leads me to believe that 

 they are delicate organs of an exalted sense of touch, analogous to 



* " The Myology of the Chiroptera." By Alexander Macalister, M.B., Ac- 

 Phil. Trans. Koy. See. 1872, pp. 125-171, plates 13-16. 



