PREFACE xi 



The use of technicalities has been avoided as far as possible, 

 and these are included only where, their omission would be at 

 the expense of clarity. The introductory chapter has been 

 designed to explain the meaning of the few scientific terms 

 whose use has proved unavoidable, as well as to illustrate 

 some of the more characteristic features of the Cetaceans and 

 Fishes, so that the reader may have no difficulty in following 

 the descriptions of the various forms given in later pages. 



A few words are necessary concerning the scientific names 

 that have been used for the fishes. With the 6-foot rule as the 

 standard for inclusion, it follows that we shall sometimes be 

 dealing with a whole family of fishes, sometimes with the 

 members of a single g^nus, and sometimes with one or more 

 species selected from a genus. Immediately in front of each 

 description is given the popular name or names of the fishes 

 dealt with therein, and the scientific name of the family or 

 genus (sometimes both) to which they belong. For convenience 

 it has been considered preferable to retain in this book the 

 larger and more conservative generic groupings favoured by 

 the older naturalists, so that the generic names employed for 

 certain forms may not correspond with those to be found in 

 some modern works on fishes. Since modern authorities 

 themselves are by no means in agreement as to the limits of 

 fish genera, or as to the names by which they are to be called, 

 the advantage of this plan appears clear. To take an example, 

 in the case of the Blue Sharks or of the Whip-tailed Sting Rays, 

 & number of species have here been grouped together under 

 the generic names Carcharinus and Trygon respectively, but 

 many modern authorities would subdivide each of these groups 

 into several distinct genera. 



Finally, the authors wish to take this opportunity of thanking 

 Lieut. -Col. W. P. C. Tenison, D.S.O., for his collaboration and 

 for the care and skill that he has displayed in the preparation 

 of the illustrations. All these have been drawn specially for 

 this book, from specimens in the British Museum (Natural 

 History), as far as these were available. 



J. R. N. 

 London, 193;: F. C. F. 



