240 On the Arctic Form of the Nutcracker. 



form appears to be a resident^ and to be, to all intents and 

 purposes^ identical with the resident form of Europe. The 

 white spots^ both on the upper and nnderparts, and on the 

 ends of the tail-feathers, are rather more developed in the 

 Japanese birds than in the resident European ones, but not 

 so much so as in examples from Siberia. 



This constant mtiltiplication of subspecific forms becomes 

 rather alarming ; but where a difference of form or colour is 

 correlated with a diffei'ence of geographical distribution, it is 

 impossible for ornithologists to ignore the fact. In future 

 no monograph of a species can be regarded as complete with- 

 out a sentence referring to the amount of local variation to 

 which it is subject. 



There are three other Nutcrackers belonging to the genus 

 Nacifraga, and they all vary nearly as much as their Palse- 

 arctic ally : — 



Height of bill. White on tail, 

 in. in. in. in. 



K multisfriata -41 to -5 2-4 to 1-9 



N. hemispila -49 to "6 3-0 to 22 



N. Columbiana "4 to "48 entirely white. 



It is not known that any of these variations have a geo- 

 graphical significance, and therefore the extreme forms are 

 not regarded as subspecifically distinct. The subject of the 

 nomenclature of subspecies is a very difhcult one, and it is 

 not at all impossible that it will hereafter be found that the 

 pre-Linuean practice of disci'iminating them by a sentence, 

 instead of a word, is the only scientific method of dealing 

 with them. 



The introduction of a trinomial nomenclature has been an 

 inestimable boon to ornithology, preventing subspecies from 

 being on the one hand erroneously elevated to specific rank, 

 or on the other hand ignored altogether ; but there seems 

 reason to fear that the use of trinomials is being abused. 

 Dr. Stejneger, to whom we are greatly indebted for much new 

 and important information respecting Palsearctic birds, de- 

 scribed a Nuthatch from Yesso (the north island of Japan) 

 under the name Sitta amurensis clara (Proc. U. States Na- 



