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THE POPULAR SCIENCE MONTHLY. 



over, quite good eating themselves. So tliere should be made a dis- 

 tinction between them as between the venomous and the harmless ser- 

 pents and the more and the less poisonous spiders. 



Perhaps one element of distrust of the bat family arises from 

 their apparent non-conformity to either of the common animal types. 

 The bat seems to be either a bird witli hair and teeth, bringing forth 

 its young alive, or a mammal with wings, and the general aspect and 

 habit of a bird. Add to these exceptional features that their attitude, 

 when at rest, is always head downward, and that their legs are so 

 turned outward as to bring the knees behind instead of in front, 

 and we may almost pardon the common dislike of the whole family 

 of bats. 



Fig. 4. FLriNG-Fox oe Roussette {Pteropus rubricollis) 



We may as well state at once that a bat is really a matmnal ; that 

 is, it agrees with moles, rats, sheep, horses, cats, monkeys, and men, 

 in bringing forth its young alive, and nursing them by milk ; in hav- 

 ing red blood-corpuscles, which contain no nucleus ; in being clothed 

 with hair; and in possessing a corpus callosum, that is, a band of 

 fibres connecting the two cerebral hemispheres. 



There are other anatomical features which link the bats closely 

 with the moles and shrews and hedge-hogs. Indeed, the bat might be 

 described as a flying mole, or tlie mole as a burrowing bat. 



Twenty years ago one of these phrases might have been as accept- 

 able as the other ; for they would have implied only an ideal connec- 

 tion between the forms. But now, wdien the idoa of an actual evolu- 

 tion or derivation of widcly-difterent forms from me another, or from 

 common stocks, is rapidly becoming the fundamental postulate of all 

 biological research, we are bound to inquire whether one mode of ex- 

 Dression is not much more likely to be true than the oiher. 



