TRINOMIAL NOMENCLATURE IN ZOOLOGY. 245 



the West, and these fonns, althougli somewhat alike, were also 

 differentiated as species, distinct from those found in the East, 

 and were so named. But still later, large collections were 

 gradually amassed from the intervening regions of the great 

 interior, and these were elaborately studied (in collections some- 

 times of hundreds), and many were the ' Eastern and Western 

 so-called species thereby connected. But then it became evident 

 that something more should be done than merely lock together 

 into one heterogeneous fold forms so different. Then it was that 

 this trinomial system came into use as a very convenient tool for 

 the distinction of the various intermediate forms. Ultimately a 

 philosophy became the result of study and practice, so that now 

 we can at once, by the inspection of a catalogue, approximately 

 ascertain whether the forms are radically distinct, what variation 

 exists between the extremes of form, and by the trinomial 

 names, whether a given species is variable and whether it is 

 manifest under a number of modifications. 



In this trinomial system we have an example of a scheme by 

 which we can become cognizant of tlie amount, to a certain 

 extent, of variation in a given group. By this convenient means 

 we are also enabled to differentiate the characters, and to give at 

 once to the mind of the reader or student some idea of the range 

 of chai-acters that may be deemed to prevail in a certain group. 



Turning to Dr. Coues's request for information with regard 

 to other groups. Dr. Gill said that it was true that we have in 

 other groups a similar applicability of these principles. A 

 number of examples are afforded in the case of the fishes, insects, 

 and moUusks, where the naturalist is compelled to degrade some 

 forms and admit them as simple variations and sub-species. This 

 scheme would also come in as a convenient tool for the differentia- 

 tion of recent from fossil forms, there being a number of extinct 

 forms very much like those now existing, which are regarded by 

 some as conspecific and by others as different, receiving different 

 names. 



Prof. Wm. H. Brewer remarked that, as a matter of con- 

 venience, this was about the only way that we could scientifically 

 describe many varieties of cultivated plants and breeds of 

 domesticated animals, which differ from one another much as 

 species do, the differences, however, being less constant. Already 

 some agricultural writers, who have knowledge of natural history 



