240 M. I. G. Saint-Hilaire on an American Bat. 



Asia and America resemble each other in the form of the teeth 

 and body, the disposition of the wings, and even in size ; it is the 

 same also in regard to colour ; in a word every thing is so similar in 

 the two, that the figure of one might almost be taken for the figure 

 of the other, and if the two animals were inhabitants of the same 

 region, one would be tempted to unite them in a single species. 



How remarkable a fact, that all these similitudes and relations 

 should exist between the individuals, and yet the countries 

 which respectively produce them be separated by an almost in- 

 finite tract of ocean ! 



So striking a resemblance in point of form, and such intimate 

 relations existing between animals whose native countries are so 

 widely separated, might almost lead to the conclusion, that lo- 

 cality should be struck out from the list of distinctive characters. 

 I am not however of that opinion. We must not forget, that the 

 truth of the idea, which I have just proved erroneous, seemed 

 demonstrated by the experience of ages, and consequently that 

 the exceptions to the rule are very rare. Difference of country 

 neither can, nor will any longer be a proof of difference of or- 

 ganization, but it can and must always be an indication of it : it 

 can no longer prove it, but it ought always to make us suspect 

 it ; in a word, it can no longer command, but it can always 

 counsel, and thus the Naturalist, without blindly following the 

 route it points out, ought carefully to collect its indications, that 

 he may advance with firmer and surer step in the path he has 

 thought fit to pursue. I will not conclude without reminding the 

 Reader, that the establishment of the genus Nyctinomus, forms 

 a part of my father's numerous labours on the Bats. This cir- 

 cumstance, however indifferent to the public, enhances the value 

 of my debut in the science, in my own estimation, since I am per- 

 mitted to consider my present labour as a feeble branch, en- 

 grafted by myself, ou the stem produced by my father. 



