4 GENEKAL EVOLUTION. 



To find exampbs of wliat is asserted, it is only necessary tp refer 

 to the diagnostic tables and keys of the best and most honest 

 zoologists and botanists. It is true that these 'diagnoses are dry 

 reading to the non-professional, yet they embrace nearly all that is 

 of value in this part of biological science, and must be mastered in 

 some department before the student is in possession of the means 

 of forming an opinion. The neglect to do this explains why it is 

 that, after all that has been written and said about protean spe- 

 cies, etc., the subject should be so little understood. 



It is true that in but few of these cases have the varieties been 

 seen to be bred from common parents, a circumstance entirely 

 owing to the difficulties of observation. The reasoning derived 

 from the relations of differences appears to be conclusive as to 

 their common origin, unless we are prepared to adopt the oppo- 

 site view, that the varieties have originated separately. As these 

 avowedly grade into individual variations, we must at once be led 

 to believe that individuals have been created independently — a 

 manifest absurdity. 



But variations in the same brood have been found among wild 

 animals ; for example, both the red and gray varieties of the little 

 horned owl {Scops asio) have been taken from the same nest. 



As further examples of gradation between species and variety, 

 found in nature, I only have to select those genera most numerous 

 in species, and best studied. Among birds, Corvus, Empidonax, 

 Biiteo, Falco, etc. Reptiles, Eutaenia, Aiiolis, Lycodoji, Naja, 

 Caudlsona, Elaps, Oxyhrropus, etc. Batrachia, Rana, Hyla, 

 Clioroj)Mlus, Borhorocoetes, Amblystoma, Spelerpes, etc. Fishes, 

 Ptycliostomus, Plecostomus, Amiurus, Salmo, Perca, and many 

 others. 



In all these groups of species, or '^'genera," it is impossible in 

 some cases to determine what is variety and what species. This 

 is notoriously the case with the salmon and trout {Salmo), for one 

 of the greatest opponents of close division of species. Dr. Gilnther, 

 of London, thought himself necessitated, a very few years ago, to 

 name and describe half a dozen new species of trout from the 

 lakes of the British Islands, and, from being a stanch supporter 

 of the old view of distinct creations, was completely converted to 

 evolutionism. 



Such is one of the views which has forced conviction on the 

 minds of thoroughly honest men who were not only desirous of 

 knowing the truth, but were in many cases brought over from a 



