316 Mr. H. J. Elwes on Modern [Ibis, 



as my starting-point. In it he expressed what is in my 

 opinion a sound idea, when he stated at the end o£ his letter 

 that " the fonnchition of the subspecies is an unstable variation 

 and in consequence the structure is collapsing," In a letter 

 by Dr. Lowe and Mr. Mackworth-Praed (Ibis. 1921, p. 344) 

 they say that Mr. Loomis's letter will be welcomed by many 

 ornithologists on this side of the Atlantic, and not least by 

 some of those who might be termed subspecies men. They 

 go on to say that trinomialism supplies a handy (not 

 invariably handy) adjective \\ hich is internationally under- 

 stood and which designates birds from a certain locality 

 (may I add, and often very ill-defined or uncertain locality 

 or separate localities) in a short and concise way (may 

 I qualify this by saying that, in the hands of some fol- 

 lowers of the subspecies mania, the differential characters 

 are anything but short or concise) ; and that " in some cases 

 the recognition of subspecies enables us to map out migra- 

 tion routes of birds from any given locality, and to note the 

 effect of environment on any given species throughout its 

 range." They further say that they do not believe that 

 natural selection as defined by Darwin can have any practical 

 effect on the actual formation of species, nor do they believe 

 in the direct action of environment on the formation of 

 new species. They then point out that there are at least 

 two forms of variation, one known as " mutational" and the 

 other as " environmental," and thar many of our present- 

 day subspecific forms would probably quickly disaj)pear if 

 the orpanisni were transferred from its normal environment 

 to some other of a different nature. On this there is plenty 

 of evidence among mammals and plants if not among birds. 

 They conclude a very valuable and thoughtful letter by 

 saying that it behoves us to set our subspecific house in 

 order with a view to defining more accurately the exact 

 rank of our subspecies. They do not suggest how this is to 

 be done. Neither can I do so under the existing rules. 



These letters were reviewed by Col. Meinertzhagen in a 

 most valuable and careful paper (Ibis, 1921, p. 528), " Some 

 thouohts on Subspecies and Evolution," which discusses 



