28 



These examples appear to be sufficient to demonstrate that it is the 

 plan and not the speciality of structure or organization that indicates the 

 rank of groups. 



The number of species described in the Catalogue, nominally amounts 

 to three hundred and ninety-four. It it is probable that when the species 

 are thoroughly investigated, the number will be considerably reduced, 

 and that many now retained with hesitation as distinct, will be identified 

 with previously known ones. Those species that are most doubtful have 

 been indicated by an asterisk (*) after the specific name. One or two, of 

 which the genus is doubtful, has been pointed out by the same character- 

 placed after the generic part of the name of the species ; when one has 

 been introduced on doubtful authority as an inhabitant of the coast, the 

 same is placed before the specific name. The describers of most of the 

 doubtful " new species " were acquainted by description with those to 

 which they are most nearly allied, and had, consequently, better sources 

 of information than ourselves. We have, therefore, not deemed it in most 

 instances proper to attempt a positive indentification, when there was a 

 reasonable doubt, the object of this Catalogue being to present a 

 complete view of the species that have been described. In some cases, 

 descriptions of species have been very meagre, and no distinctions are 

 mentioned by which they can be distinguished from others. In other 

 instances, the descriptions have been very full and complete ; but the 

 species have been indicated with a doubt, either on account of the poverty 

 of a former description of an allied species, or from inability to refer at 

 present to the work in which the description occurs. 



The Catalogue is only intended to embrace those species found on some 

 portion of the eastern American coast, from Greenland or the Arctic 

 regions to the State of Georgia. South of that, the West Indian Fauna 

 commences, and quite a different association of forms and species occurs. 

 At a future time, a catalogue of the West Indian fishes will be probably 

 published. 



In the preparation of the Catalogue, and the acceptation of both 

 generic and specific names, we have been always guided by the law of 

 priority, except when a palpable error would be perpetuated. It may not 

 be apparent, from the list, by whom the species was originally described 

 or named. In most cases, it will be discovered on reference to the works 

 of Doctors Storer, Dekay, or Holbrook. In others, it has been found 

 that species have been named by naturalists which have been unknown 

 or not identified by those naturalists. Such instances we hope soon to 

 be able to publish our observations on. 



Many new genera have been introduced here for the first time. We 

 have been compelled to this step in order not to mislead the student in 

 regard to their generic affinities. Several well-known names have also 

 been replaced by new ones, as the former had been already preoccupied 



