27 



spite of all the shooting ; but if you limit the ground suitable 

 for them, comparatively speaking, to a small pond or a single 

 marsh, and then persecute them, they must be driven away. 

 Birds like to have room to choose particular places to feed at, 

 and, if they cannot find such places here, their great powers of 

 flight enable them to find them elsewhere. C. M. A. (New- 

 castle-upon-Tyne. 



ON WHAT ARE CALLED GENERA AND SPECIES. 

 .(Reprinted fawn " The Field," Dec. 26th, 1863.) 



WHEN I first began to take an interest in Natural History J 

 fancied the terms genus and species were easy to understand ; 

 but it is now long since I became acquainted with the many dif- 

 ficulties which arise before a conclusion can be arrived at. The 

 former term appears to have no definite meaning : it may either 

 comprise a whole division, as the fishes or the .birds, or a parti- 

 cular tribe of each division, as the butterflies or the hawks ; or 

 it may be used in a very limited extent, and comprise only one 

 or any greater number of what are called species, according to 

 the fancy of any individual. It is certainly useful to have what 

 are called genera, by which nearly allied species can be classed 

 together ; but when so many genera are recognised as at present, 

 you may almost as well separate each species into a genus at 

 once. The term species is much more difficult to deal with. 

 Before endeavouring to determine what constitutes a species, 

 would it not be well to expunge those animals which have been 

 in a state of domestication for a great length of time ? and for 

 this reason that it is at the present day quite impossible to trace 

 back what they originally sprang from, and also to trace by what, 

 if by any means, such animals may have got distributed over the 

 various portions of the globe. In some instances, climate, food, 

 and (having escaped) running wild almost in a state of nature, 

 and other causes, probably have effected such changes, that ani- 

 mals descended from the same original stock are now by many 

 persons considered different species ; and on one being brought 



