Classification of Fishes 375 



todes gillii, Liparis agassizi. In recent custom all specific names 

 are written with the small initial; all generic names with the 

 capital. 



One class of exceptions must be made to the law of priority. 

 No generic name can be used twice among animals, and no 

 specific name twice in the same genus. Thus the name Diabasis 

 has to be set aside in favor of the next name H&mulon, because 

 Diabasis was earlier used for a genus of beetles. The specific 

 name Pristipoma humile is abandoned, because there was al- 

 ready a humile in the genus Pristipoma. 



The Conception of Genus. In the system of Linnaeus, a genus 

 corresponds roughly to the modern conception of a family. 

 Most of the primitive genera contained a great variety of forms, 

 as well as usually some species belonging to other groups dis- 

 associated from their real relationships. 



As greater numbers of species have become known the earlier 

 genera have undergone subdivision until in the modern systems 

 almost any structural character not subject to intergradation 

 and capable of exact definition is held to distinguish a genus. 

 As the views of these characters are undergoing constant change, 

 and as different writers look upon them from different points of 

 view, or with different ideas of convenience, we have constant 

 changes in the boundaries of genera. This brings constant 

 changes in the scientific names, although the same specific name 

 should be used whatever the generic name to which it may be 

 attached. We may illustrate these changes and the burden of 

 synonymy as well by a concrete example. 



The Trunkfishes. The horned trunkfish, or cuckold, of the 

 West Indies was first recorded by Lister in 1686, in the descrip- 

 tive phrase above quoted. Artedi, in 1738, recognized that it 

 belonged with other trunkfishes in a group he called Ostracion. 

 This, to be strictly classic, he should have written Ostracium, 

 but he preferred a partly Greek form to the Latin one. In the 

 Nagg's Head Inn in London, Artedi saw a trunkfish he thought 

 different, having two spines under the tail, while Lister's figure 

 seemed to show one spine above. This Nagg's Head specimen 

 Artedi called "Ostracion triangulatus duobus aculeis in fronte et 

 totidem in imo venire subcaudalesque binis." 



Next came Linnaeus, 1758, who named Lister's figure and 



