lo POPULAR SCIENCE MONTHLY. 



known or earliest studied. Tlius all lampreys constitute the family 

 Petromyzonidfe. 



An order may contain one or more families. An order is a division 

 of a larger group; a family, an assemblage of related smaller groups. 

 Intermediate groups are often recognized by the prefixes sub or super. 

 A subgenus is a division of a genus. A subspecies is a geographic race 

 or variation within a species; a superfamily, a group of allied families. 



Binominal nomenclature, or the use of the name of genus and 

 species as a scientific name was introduced into science as a systematic 

 method by Linnaeus. In the tenth edition of his 'Systema Naturae' 

 published in 1758, this method was first consistently applied to animals. 

 By common consent, the scientific naming of animals begins with this 

 year, and no account is taken of names given earlier, as these are, ex- 

 cept by accident, never binomial. Those authors who wrote before 

 the adoption of the rule of binomials and those who neglected it are 

 alike ruled out of court. The idea of genus and species was well under- 

 stood before Linnaeus, but the specific name used was not one word 

 but a descriptive phrase, and this phrase was changed at the whim of 

 the different authors. Examples of such names are these of the West 

 Indian trunk-fish, or Cuckold: Ostracion tricornis of Linnaeus. Lister 

 refers to a specimen in 1686 as Piscis triangularis capiti cormitis cui 

 e media cauda cutanea oculeus longus erigitus. This Aretdi alters in 

 173i8 to Ostracion triangulatus aculeis duoius in capiti et unico longioro 

 superne ad caudam. This is more accurately descriptive and it recog- 

 nizes the existence of a generic type, Ostracion, or trunk fish, to cover 

 all similar fishes. French writers transformed this into various 

 phrases beginning: C off re triangulaire a trois comes or some similar 

 descriptive epithet, and in English or German it was likely to wander 

 still farther from the original. But Linnaeus condenses it all in the 

 word tricornis, which although not fully descriptive, is still a name 

 which all future observers can use and recognize. 



It is true that common consent fixes the date of the beginning of 

 nomenclature at 1758, but to this there are many exceptions. Some 

 writers date genera from the first recognition of a collective idea under 

 a single name. Others follow even species back through the occasional 

 accidental binomials. Most British writers have chosen the final and 

 completed edition of the ' Systema Naturae, ' the last work of Linnaeus ' 

 hand in 1766, in preference to the earlier volume. But all things con- 

 sidered, justice and convenience alike seem best served by the use of 

 the edition of 1758. 



Synonymy is the record of the names applied at different times to 

 the same group or species. With characteristic pungency Dr. Coues 

 defines synonymy as *a burden and a disgrace to science.' It has been 

 found that the only way to prevent utter confusion is to use for each 



