366 PALEONTOLOGY 



trivial name must be altered, because they regarded the 

 exact duplication of generic and trivial names as bar- 

 barous. For example, Martin, in 1809, named a certain 

 brachiopod Anomites productus. J. Sowerby, in 1812, took 

 it as the type of a new genus, which he called Productus, 

 and changed Martin's species into Productus martini (quite 

 rightly according to the Stricklandian code). Later 

 zoologists have rejected this exception to the law of 

 priority, and the fossil which has long been known as 

 Productus martini must be called P. productus (Martin). 



4. As knowledge increases and becomes more exact, 

 a later author may transfer a species from its original 

 genus to another. Thus Cheirurus insignis Beyrich, 1845, 

 is a synonym of Pavadoxides bimucronatus Murchison, 

 1839. The law of priority here settles that the earlier 

 trivial name must stand ; but as it was recognized that 

 Pavadoxides bimucronatus Murchison was not a true 

 Pavadoxides, it was transferred to Beyrich's new genus 

 Cheirurus, but the trivial name having priority over 

 Beyrich's name insignis, it stands as Chemirus bimucronatus 

 (Murchison), the author's name being placed in 

 parentheses as an indication that an alteration in the 

 generic name has been made. An alternative way of 

 expressing this is Cheirurus bimucronatus Murchison sp. 



As an example of the importance of these distinctions, 

 which may at first appear an unnecessary refinement, 

 we may take the following case : James Sowerby, in 

 1818, gave to a lamellibranch the name Cardita deltoidca ; 

 in 1820 he gave to another the name Venericardia deltoidca. 

 In 1826 J. de C. Sowerby made a new genus, Pholadomya, 

 into which he moved the former of the above species. 

 In 1871, S. V. Wood transferred the latter of the 

 two from Venericardia to Cardita. Thus we "find that 

 Cardita deltoidea (J. Sowerby) is quite a different thing 

 from Cardita deltoidea J. Sowerby : 



