GENERAL FACTS ABOUT SEA FISH 5 



names, a matter rather of convenience for the collaboration of 

 ichthyologists of all nations. Were it not for some such 

 understanding, it is dreadful to think of the loss of time and 

 labour that would necessarily be involved in such an under- 

 taking as the forthcoming international investigation of the 

 North Sea. 



Those who have made it their business to arrange and 

 rearrange the fishes in families, genera, and species have relied 

 upon more or less well-marked characters, such as the presence 

 or absence of sharp spines in the fins. This system has 

 its advantages, but the differences of opinion among those 

 qualified to pronounce on such matters have been some- 

 what disconcerting to the student. Even in naming the fins, 

 Mr. Cunningham and a few other modern workers deliberately 

 depart, as will presently be shown, from the older nomen- 

 clature ; and such a course, whatever evidence it may afford of 

 originality, is most distressing when it becomes necessary to 

 compare the statements of different authorities. As to arrange- 

 ment of the families in order of precedence, writers on fishes 

 show as much diversity of opinion as ornithologists. Just as 

 some of the latter give precedence to the birds of prey, while 

 others prefer to open their treatise with the crows and thrushes, 

 so does Couch commence with the sharks, while Day gives 

 first place to the perches ; and the authors of the sumptuous 

 volumes on the Scandinavian Fishes, so frequently alluded to 

 in the following pages, open their account with the wrasses. 

 In following Couch and taking the sharks and rays first, the 

 writer has not desired to indicate any anatomical priority, but 

 rather to preface the life-stories of the smaller and more 

 familiar fishes with some account of the largest and most 

 striking. If other reason were necessary, it might not perhaps 

 be difficult to justify this preference for the sharks, on the 

 ground of their undoubted antiquity. Almost all modern 

 writers are agreed that the sharks and rays have come down 

 to us as survivals of very ancient and important fish-families, 



