FIELD NATURALISTS' CLUB. 165 



groups, those I have given are sufficient to identify them. 

 The wings of bats consist of a membrane which has its origin 

 on the sides of the neck. It was once believed that this mem- 

 brane is of a callous nature but experiments made by Spal- 

 lanzanni and others have proved that it is a very sensitive 

 organ. I had an Artibeus alive for some time in a large cage, 

 the bat being apparently asleep, I took a thread and merely 

 touched this membrane, this excited nervous movements and the 

 animal was evidently uneasy for some time. The fingers in bats 

 are developed to an extraordinary degree and they thus serve 

 to stretch the flying membranes, when in use, just as the ribs of 

 an umbrella keep its covering open. The hinder limbs can scarcely 

 be called organs of locomotion for the creature is exceedingly 

 awkward when placed on the ground, walking or creeping very 

 much like a sloth when in similar circumstances. In regard to 

 their geographical distribution bats are found almost all over the 

 world but principally in the tropical zone, where the largest 

 number of species are known, in fact they are supposed to be the 

 characteristic type of mammals in the tropics, only a few species 

 inhabiting northern climes. The distinctive appearance of the 

 two groups, as given above, enables us to decide off hand to which 

 of the two great sub-orders any particular individual may belong, 

 yet the observations made by naturalists show that a few species 

 deviate in their habits from the rule indicated by these distinctive 

 characteristics. For instance, in the case of Noctilio leporinus the 

 food has varied considerably, probably owing to a gradual adapta- 

 tion of habits to altered conditions of life. The species, which is 

 widely distributed in Central and South America and is rather 

 common in Trinidad, lives under roofs of houses but principally in 

 caves. This bat is stated by no less an authority than Linmeus to 

 be a fruit-eating bat, and is referred to by him as Victi/ausfnictibus 

 arborum though its characteristic dentition and other peculiarities 

 place it among the insect eaters. Dobson found some fruit seeds 

 in the stomach of a specimen sent to the British Museum, 

 apparently the seed of Morns tinctoria. But other naturalists 

 ((iosse and von Tschudi) remarked that it lived in hollow 

 trees and feeds on beetles ; I have examined many stomachs my- 

 self and often found the tibiae of beetles in them. But now, strange 

 to say, the species has shown a still more remarkable deviation 

 from its original habits. It has given up its diet of fruit and beetles 

 and has taken to fishing in salt and fresh water. The first account 

 of this new custom is that of Mi-. Fraser who observed it in 

 Ecuador. There he saw the bats skimming the bank of the 

 river at Esmeralda, every now and then making a dash along 

 ami actually striking the water, catching in their swift career 

 minute fish which were incautiously swimming near the sur- 

 face. Sometime in January 1892 I accompanied the late Mr. 



