PRIORITY AND SYNONYMY 915 



accepted name for the species described by Conrad as Delthyris 

 mucronata in 1841. One of the numerous varieties of this species 

 had, however, been descrii)ed by Atwater in 1820 as Terebratiila 

 pcniiata, and it has lience lieen argued that Spirifer pennatus and 

 not Spirifer tiiucroiiaftis should be the name of the species. Spirifer 

 pennatus has, however, come into use for another species, described 

 under that name by Owen in 1852. The adoption of Atwater's 

 name requires not only the discarding of a well-known and appro- 

 priate name, but also requires the substitution of another name 

 for ( )wen's Spirifer pennatus. This strict adherence to the rule of 

 priority in this case would lead to so much confusion that it is much 

 better to make an exception and retain the names which have been 

 so extensively used in the literature. 



In the example cited, the name pennatus has been given to two 

 species of Spirifer by different authors. That we may know which 

 species is meant, it is necessary to write the name of the author 

 after the specific name. Thus, in the case cited, the names should 

 be written: Spirifer pennatus (Atwater) and Spirifer pennatus 

 Owen. This custom of adding the author's name is a general one, 

 and should always be observed in all but the most general dis- 

 cussions. When the author of the species has placed it in the 

 wrong genus, or if the species is subsequently referred to a new 

 genus, the author's name after the species is placed in parentheses, 

 and frequently the name of the person who first placed the species 

 in the correct genus is added. Thus, in the examples cited above, 

 Conrad described his species under the generic name Delthyris, but 

 it belongs to the genus Spirifer; hence the name is written Spirifer 

 mucronatus (Conrad). Since Billings was the first to place the 

 species in the genus Spirifer, his name may be added, viz., Spirifer 

 mucronatus (Conrad) Billings; but this method is not always 

 adopted. Sometimes the form Spirifer mucronatus Conrad sp. is 

 used. 



Synonymy. 



No genus can have two species of the same name. If two 

 authors describe, under the same name, two different species of the 

 same genus, the one to which the name was first applied retains it, 

 the name becoming a synonym so far as the other species is con- 

 cerned ; for this later-described species a new name must be pro- 

 posed. When reference to the first-described species is made, it is 

 often desirable .to note the fact that the name has been applied to 

 another species to avoid possible confusion. Thus Dunker in 1869 



